Given: f(x)=ax+b, where a and b are constants, f(-1)=10, and f(5)=f(2)+f(3). Find f(12) Please help... too many unknowns and I don't know where to start!

Question

Given: f(x)=ax+b, where a and b are constants, f(-1)=10, and f(5)=f(2)+f(3). Find f(12) Please help... too many unknowns and I don't know where to start!

Answer 1

a +b = 10

b = a +19, f(x) = ax +a + 19= a(x+1) + 19

f(5) = f(2) + f(3) = 6a + 19 = 3a +19 + 4a +19

7a + 38 = 6a + 19

a = -19, b=0

f(x) = -19x

f(12) = -19(12) = - 228