Question

(TEN POINTS)

Answer 1

F(-1)= -3 is (-1,-3) and f(2) = 6 is (2,6) where f(x) = y
y=mx + b is the slope-intercept form whereas m equals the slope (rate of change) and b equals the y-intercept (initial amount/what y is when x is 0.)

First, we need to find the slope between the two points (-1,-3) and (2,6). To find the slope we could use one of it's formulas $\frac{y^2 - y^1}{x^2 - x^1}$.  
1. (-1,-3)
2. (2,6)
$\frac{6 - -3}{2 - -1}$ → $\frac{9}{3}$ → $\frac{3}{1}$

The slope is 3 ($\frac{3}{1}$). Thusly, y = 3x + b

To find out the y-intercept, we can reverse the slope. [Note: This $\frac{3}{1}$ is in $\frac{rise}{run}$ where rise is 'y' and run is 'x'. Reversed would be $\frac{-3}{-1}$ ]. Take the second ordered pair and use our reversed slope on it until we get 0 for x. 

(2, 6) ⇒ (2 - 1, 6 -3) ⇒ (1, 3) ⇒ (0,0)

Y-intercept is 0. Therefore, y= 3x + 0 [NOTE: y = f(x), so if you want it in function notation form it's just f(x) = 3x + 0.]