Question

In the 2nd week of the year Carrie had $700 in her savings account. At 5 weeks she had $325. What is the equation that represents this situation?

Answer 1

Answer: x=-125+950

Explanation:

The value went from 700 to 325 in 3 weeks

700-325= 375 /3 =125

0=950

1=825

2=700

3=575

4=450

5=325

Answer 2

y = 125x + 75

Explanation:

Let x represents the week and

Let y represent the balance

When x = 2, y = 325.

This means

(x1,y1) = (2,325)

When x = 5, y = 700

This means

(x2,y2) = (5,700)

Required

Determine the equation

First, we need to solve for m, the slope

m = ∆y/∆x

i.e.

m = (y2 - y1)/(x2 - x1)

Substitute values for x and y

m = (700 - 325)/(5 - 2)

m = 375/3

m = 125

Next, we calculate the equation in slope intercept form using

y - y1 = m(x - x1)

Substitute values for m, x1 and y1

y - 325 = 125(x - 2)

y - 325 = 125x - 250

Collect like terms

y = 125x - 250 + 325

y = 125x + 75

Hence, the equation is:

y = 125x + 75