Test B review, no calculators please help

Question

Answer 1

21)

The line equation y = ax + b

Compare it to slope-intercept form y = mx + b,

Where m is slope and b is y intercept

In this case a is slope and b is y intercept.

Observe the graph, the y intercept of line is negative.

A negative y intercept means that the line crosses below the origin.

And the line has positive slope.

If line has positive slope, then the y coordinate increases as the x coordinate increases so the line slopes upward.

So a > 0 and b < 0

If one of the  factors is negative, the product will be negative.

Therefore, ab < 0

Option (a) is correct.

Answer 2

22) The piecewise function

f(x) = x - 9

f(2) = 2 - 9

f(2) = - 7

   Option (b) is correct.