Answer:
Step-by-step explanation:
1) Make it so that it's easy to solve
3 = -y +2x
18 = y + x (the y cancels out)
21 = 3x (divide both sides by 3 to isolate x)
x = 7 (then you can plug in x and then solve for y)
2) Again, make the problem easy to read
12 = -x + y
27 = 4x + 2y (get rid of either x or y. I am going to get rid of x by multiplying the top equation by four)
48 = -4x + 4y
27 = 4x + 2y (x is canceled out)
75 = 6y (divide both sides by 6 to isolate y)
12.5 = y (then plug in y to find x)
3) 15 = (7 + p) + p -----------------> p represents pants and (7 + p represents shirts because she bought 7 plus pants of shirts)
15 = 7 + 2p
8 = 2p (isolate p by dividing by 2)
p = 4
- Elaine bought 4 pants and 11 shirts.
In the comments, let me know if you need a further explanation.