Question

you buy 5 pairs of jeans and 10 t-shirts for 140$.your friend buys 3 pairs of jeans and 5 t-shirts for $79. write and solve a system of linear of the equation by elimination

Answer 1

Jeans=18

Shirts=5

5j+10s=140

3j+5s=79

Explanation:

1) 5j+10s=140 multiply the bottom row by -2.

-2(3j+5s=79)

2) 5j+10s=140 add the top and bottom row.

-6j-10s=-158

3) -j= -18 variable one found.

4) 5(-18) + 10s = 140 substitute j .

5) 90 + 10s = 140 subtract 90.

6) 10s = 50 divide by 10.

7) s = 5 variable 2 found.

8) 3(18) + 5(5) =79 check for accuracy by substituting both.

9) 54 + 25 = 79 solve.

Answer 2

J = jeans

T = t-shirts

You: 5j + 10t = 140

Friend: 3j + 5t = 79

To use elimination in this problem, multiply the second equation by -2 so that 10t and 5t can cancel out:

5j + 10t = 140

-6j - 10t = -158

We are left with -j = -18 or j = 18

Substitute 18 into any equation. I'll use the first equation:

5(18) + 10t = 140

90 + 10t = 140

10t = 50

t = 5