Question

Write an equation, and solve

An electrician has a 20-ft wire. He needs to cut the wire so that one piece is 4 ft shorter than the other. What will be the length of each piece?​

Answer 1

12, 8

Explanation:

So we have the following things we need to check for:

1. Both wires add up to 20 ft.

2. One wire is 4 ft longer than the other.

In order to do this we can create the following two equations (I'll call the wires a and b)

`a + b = 20\\a = b - 4`

Next we substitute equation two into equation one and solve for b.

`a + b = 20\\ (b - 4) + b = 20\\ 2b - 4 = 20\\2b - 4 + 4 = 20 + 4\\2b = 24`

`(2b)/(2) = (24)/(2)\\b = 12`

And lastly we solve equation 2 using the new value of b.

`a = b - 4 = 12 - 4 = 8`

So the wires are 12 and 8 feet.