You can use Substitution to solve this problem:
4x-y=20
-y=-4x+20
y=4x-20
Now you have two equations, and you use the first one to substitute into the second one.
y=4x-20 and -2x-2y=10
-2x-2(4x-20)=10
-2x-8x+40=10
-10x+40=10
-10x=-30
-x=-3
x=3
Now that we have figured out what x is, we can substitute x in to one of the equations to figure out y.
4x-y=20 x=3
4(3)-y=20
12-y=20
-y=8
y=-8
<em><u>So your answer would be x=3 and y=-8</u></em>
Answer:

Step-by-step explanation:
Let x be the original price.
( 1 - 20% ) x = 23.2



F=length of first piece=x; S=length of second piece=2x
T=length of third piece=3x
.
F+S+T=24 inches
x+2x+3x=24 inches
6x=24in
F=x=4in
ANSWER 1: The length of the first piece is 4 inches.
.
S=2x=2(4in)=8in
ANSWER 2: The length of the second piece is 8 inches.
.
T=3x=3(4in)=12 inches.
ANSWER 3: The length of the third piece is 12 inches.
.
CHECK:
F+S+T=24in
4in+8in+12in=24in
24in=24in
The factors of 16 are 1, 2, 4, 8, and 16 .
The factors of 9 are 1, 3, and 9 .