Topic Quiz A.2: Linear equations

Question 1 of 10 · Systems of two linear equations

No calculatorFill in

In the system below, the first equation is already solved for x. Use substitution to find the solution, and enter each value.

\begin{cases} x = 3y - 1 \\ 2x + 5y = 20 \end{cases}

x = and y =

Type your answer in the box. Fractions like 3/4 are fine.

Hint

The first equation tells you what x equals. Replace x in the second equation with that expression — use parentheses.

Question 2 of 10 · Solve one-variable linear equations

No calculator

Devon solved the equation 4x - 3(x - 2) = 10 as shown.

StepWork
14x - 3x - 6 = 10
2x - 6 = 10
3x = 16

In which step did Devon make his first error?

Answer choices
Hint

Check each step separately. What is (-3) \times (-2)?

Question 3 of 10 · Real-world linear equations

Fill in

A community theater sold 150 tickets for one show. Adult tickets cost $12 and child tickets cost $7. Ticket sales totaled $1,465. How many adult tickets were sold?

adult tickets

Type your answer in the box. Fractions like 3/4 are fine.

Hint

Let a = adult tickets. Then the number of child tickets is 150 - a. Write one equation for the money.

Question 4 of 10 · Write linear equations from context

The perimeter of a rectangle is P = 2l + 2w. Which equation is solved for the width w?

Answer choices
Hint

Treat P and l like numbers. Undo the +\,2l first, then undo the multiplication by 2.

Question 5 of 10 · Systems of two linear equations

A farm stand sells small baskets of strawberries for $4 and large baskets for $7. One morning it sold 64 baskets and took in $340. How many small baskets were sold?

Answer choices
Hint

Let s = small and \ell = large. Write one equation for the number of baskets and one for the money.

Question 6 of 10 · Solve one-variable linear equations

Drop-down

Select the choice that makes each statement true.

Equation 1: 2(4x - 1) + 3 = 8x + 1 has .

Equation 2: 5(x + 2) - x = 4x + 1 has .

Choose an answer from each menu.

Hint

Simplify the left side of each equation completely, then compare it with the right side.

Question 7 of 10 · Solve one-variable linear equations

Theo solved 0.5(6x + 4) = 2x - 3 as shown.

StepWork
13x + 2 = 2x - 3
25x + 2 = -3
35x = -5
4x = -1

Which statement is true?

Answer choices
Hint

Check Step 1 by distributing 0.5 yourself. Then check how Theo moved the 2x term in Step 2.

Question 8 of 10 · Real-world linear equations

Drag and drop

A tank holds 50 gallons of water. It drains at a steady rate of 2.5 gallons per minute. Drag the correct number of minutes into each box. Two numbers are not used.

  • The tank holds 20 gallons after minutes.
  • The tank is empty after minutes.

Tap a tile, then tap a box to place it.

Hint

Water left = 50 - 2.5t. Set this equal to 20, then to 0.

Question 9 of 10 · Real-world linear equations

Fill in

After a 15% raise, Dana now earns $20.70 per hour. What was her hourly pay before the raise?

$ per hour

Type your answer in the box. Fractions like 3/4 are fine.

Hint

Her new pay is her old pay plus 15% of her old pay. Write that as one number times the old pay.

Question 10 of 10 · Write linear equations from context

After an oven is turned off, its temperature drops at a steady rate. The table shows the temperature T, in °F, m minutes after it was turned off.

Minutes, m371015
Temperature, T (°F)314266230170

Which equation models the oven temperature?

Answer choices
Hint

The minutes are not evenly spaced. Divide each change in temperature by the matching change in minutes. Then work back to m = 0.

Formula sheet

Area

Area of a square s = length of a side
A = s^2
Area of a rectangle l = length, w = width
A = lw
Area of a parallelogram b = base, h = height (straight up from the base, not the slanted side)
A = bh
Area of a triangle b = base, h = height
A = \tfrac{1}{2}bh
Area of a trapezoid b_1 and b_2 = the two parallel sides, h = height
A = \tfrac{1}{2}h(b_1 + b_2)
Area of a circle r = radius (half of the diameter); \pi \approx 3.14
A = \pi r^2

Perimeter and circumference

Perimeter of a square s = length of a side
P = 4s
Perimeter of a rectangle l = length, w = width
P = 2l + 2w
Perimeter of a triangle s_1, s_2, s_3 = the three side lengths
P = s_1 + s_2 + s_3
Circumference of a circle the distance around a circle; r = radius, d = diameter, \pi \approx 3.14
C = 2\pi r = \pi d

Surface area (SA) and volume (V)

p = perimeter of the base with area B; \pi \approx 3.14

Rectangular prism l = length, w = width, h = height
SA = 2lw + 2lh + 2wh \qquad V = lwh
Right prism B = area of the base, p = perimeter of the base, h = height
SA = ph + 2B \qquad V = Bh
Cylinder r = radius of the base, h = height
SA = 2\pi rh + 2\pi r^2 \qquad V = \pi r^2 h
Pyramid B = area of the base, p = perimeter of the base, s = slant height, h = height
SA = \tfrac{1}{2}ps + B \qquad V = \tfrac{1}{3}Bh
Cone r = radius of the base, s = slant height, h = height
SA = \pi rs + \pi r^2 \qquad V = \tfrac{1}{3}\pi r^2 h
Sphere r = radius
SA = 4\pi r^2 \qquad V = \tfrac{4}{3}\pi r^3

Data

Mean (average) add all the values of the data set, then divide by how many values there are
\text{mean} = \dfrac{\text{total of the values}}{\text{number of values}}
Median
the middle value when the data are in order; with an even number of values, it is the mean of the two middle values

Algebra

Slope of a line (x_1, y_1) and (x_2, y_2) = two points on the line
m = \dfrac{y_2 - y_1}{x_2 - x_1}
Slope-intercept form of a line m = slope, b = y-intercept (where the line crosses the y-axis)
y = mx + b
Point-slope form of a line m = slope, (x_1, y_1) = a point on the line
y - y_1 = m(x - x_1)
Standard form of a quadratic equation a, b, c are numbers and a \ne 0
y = ax^2 + bx + c
Quadratic formula solves ax^2 + bx + c = 0
x = \dfrac{-b \pm \sqrt{b^2 - 4ac}}{2a}
Pythagorean theorem in a right triangle: a, b = the two legs, c = the hypotenuse (the longest side, across from the right angle)
a^2 + b^2 = c^2
Simple interest I = interest, P = principal (the amount saved or borrowed), r = rate per year as a decimal, t = time in years
I = Prt
Distance = rate × time d = distance, r = rate (speed), t = time
d = rt
Total cost
\text{total cost} = (\text{number of units}) \times (\text{price per unit})