It f(x) = 5x + 40, what is f(x) when x = -5?
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7
15

15

Step-by-step explanation:

Substitute x = - 5 into f(x) , that is

f(- 5) = 5(- 5) + 40 = - 25 + 40 = 15

y = 3x+4

step-by-step explanation:

to find the slope

slope = (y2-y1)/ (x2-x1)

    = (-8-4)/ (-4-0)

    = -12/-4

  = 3

using the slope intercept form of a line

y= mx+b

we know the slope is 3

we know the y intercept is 4 ( the point where it crosses the y axis or x=0)

y = 3x+4