a) Solve y=f(x) for x. This instruction just means to manipulate the equation so that x is all by itself on one side. We can use a mixture of addition/subtraction and multiplication/division to do this with any equation. f(x)=-3x+7 y=-3x+7 y-7=-3x (y-7)/-3=x
b) Find the input to f(x) when the output is -8. This means that it wants us to find the x value that provides a y value of -8. To solve this, we just need to plug -8 in for y and solve for x. y=-3x+7 -8=-3x+7 -15=-3x x=5
