Question

If f(x) = ax+b where a and b are constants, find a and b for f(1) = 7 and f(3) = -5. Please help

Answer 1

f(1) = 7 = a(1) + b
f(3) = -5 = a(3) + b

f(1) - f(3) => 7 - (-5) = 12 = a(1) - a(3) = a(1 - 3) = a(-2)
So a(-2) = 12
a = 12/(-2)
a = -6
using f(1) to find b
b = 7 - a(1) = 7 - (-6)(1) = 7 + 6 = 13

Ans. f(x) = -6x + 13

Answer 2

Thank you so much!!!

Answer 3

np