Question

John and Sarah are each saving money for a car. The total amount of money John will save is given by the function f(x)= 60 + 5x. The total amount of money Sarah will save is given by the function g(x)=x^2+46. After how many weeks, x, will they have the same amount of money saved? explain how you arrived at your answer.

Answer 1

Hi,
they both amount would be same  when

f(x)=g(x)

60+5x=x^2+46
x^2+46-5x=60
x^2-5x-14=0
x^2-7x+2x-14=0
(x+2)(x-7)=0

if x= weeks than x should be positive so x=7

In 7 weeks both will save same amount.