f(x)=ax+b

Question

f(-2)=27 and
f(1)=15
find the value of x when f(x)=-5

how do you work this out??

thanks so much

Answer 1

f(-2)=27 ---- > you have a point (-2,27)
f(1) = 15 -----> you have another point (1,15)

now use the method you must have learned to find a function of the form y = mx + b

( they wrote it in the form f(x) = ax + b, same thing!)