find x when F(x)=29
f(x)=-9x + 2
Not quite Saseflower (the points are for having a go )
find x when f(x)=29
$$\\29=-9x+2\\27=-9x\\\frac{27}{-9}=x\\-3=x\\x=-3$$
f(x) = -9x + 2
Plug in 29
f(29) = -9(29) + 2
Multiply -9 by 29
f(29) = -261 + 2
Add -261 and 2
f(29) = -259
And there's your answer!
Don't worry, saseflower, I misread it too, at first....!!!