Question

For the linear function f(x)=mx+b, f(-2)=11 and f(3)=-9. find m and b

Answer 1

• m = -4
• b = 3

Explanation:

Filling the given information into the equation gives two equations in two unknowns:

• 11 = m(-2) +b
• -9 = m(3) +b

Subtracting the first equation from the second, we have ...

(-9) -(11) = (3m +b) -(-2m +b)

-20 = 5m . . . . . . simplify

-4 = m . . . . . . . . divide by the coefficient of m

Putting this value of m into the first equation above, we have ...

11 = -2(-4) +b

3 = b . . . . . . . . . subtract 8

The values of m and b are -4 and 3, respectively.