Math 8 Unit 4 Review

Front

What does it mean for y to vary directly with x?

Back

It means that y is proportional to x, which can be expressed as y = kx, where k is a constant.

Front

If y = 12 when x = 15, how do you find the constant of variation (k)?

Back

You can find k by rearranging the direct variation formula: k = y/x. So, k = 12/15 = 0.8.

Front

What is the formula to find the value of x when y is given in a direct variation problem?

Back

The formula is x = y/k, where k is the constant of variation.

Front

How do you determine the y-intercept from a graph?

Back

The y-intercept is the point where the line crosses the y-axis, represented as (0, y).

Front

What is the y-intercept of the equation y = 5x + 5?

Back

The y-intercept is the value of y when x = 0, which is (0, 5).

Front

How can you identify the y-intercept from a table of values?

Back

Look for the row where x = 0; the corresponding y value is the y-intercept.

Front

What is the general form of a linear equation?

Back

The general form is y = mx + b, where m is the slope and b is the y-intercept.

Front

What does the slope (m) represent in a linear equation?

Back

The slope represents the rate of change of y with respect to x, indicating how steep the line is.

Front

How do you write an equation for a linear relationship given a starting value and a rate of change?

Back

Use the form y = mx + b, where m is the rate of change and b is the starting value.

Front

In the equation y = 40x + 150, what does 150 represent?

Back

It represents the initial amount or starting value when x = 0.