8th Grade Proportional Relationships and Slope Quiz: 10 Questions with Explanations

A \(y = 7x + 2\)B \(y = x + 7\)C \(y = 7x\)D \(y = 7 – x\)

Only \(y = kx\) has no starting amount and passes through the origin.

A 3B \(\frac{1}{3}\)C 1D 4

The y-value at x = 1 is 3. Reversing the ratio gives 1/3.

A \(\frac{3}{2}\)B \(\frac{2}{3}\)C \(3\)D \(15\)

Slope = rise over run = 9/6 = 3/2. Flipping rise and run gives 2/3.

A \(y = x + 4\)B \(y = 3x\)C \(y = 2x + 2\)D \(y = \frac{1}{3}x\)

\(6/2 = 15/5 = 24/8 = 3\).

A x: 1, 2, 3 and y: 4, 8, 12B x: 2, 4, 6 and y: 1, 2, 3C x: 1, 2, 3 and y: 4, 7, 10D x: 3, 6, 9 and y: 5, 10, 15

The ratios y/x are 4, 3.5 and 3.33, so they are not constant.

A A is steeper than BB B is steeper than AC They have the same slopeD A has the greater unit rate

Slope of B is 2 and slope of A is 1/2, so B is steeper.

A 200 milesB 450 milesC 55 milesD 250 miles

Rate = 50 mph, and 50 x 5 = 250. Adding 2 hours to 150 miles is a common mistake.

A \(0.4\)B \(6\)C \(14\)D \(2.5\)

\(k = 10 \div 4 = 2.5\).

A $18.00B $22.50C $11.00D $45.00

Hourly rate = 9/2 = 4.50, and 5 x 4.50 = 22.50.

A \(-2\)B \(2\)C \(-\frac{1}{2}\)D \(-3\)

Rise = -6 over run = 3, so the slope is -2.