math problems?

0 ⤊

solve each of the following systems by substitution.

8x - 4y = 16
y = 2x - 4

2007-07-18 11:53:56 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics

3 answers

8x -4y = 16 . . . . . . equation 1
y = 2x - 4 . . . . . . . equation 2 . . substitute to equa 1
8x - 4(2x - 4 ) = 16
8x - 8x - 16 = 16
0x = -32
undefined equation. . . no solution

2007-07-18 12:05:59 · answer #1 · answered by CPUcate 6 · 0⤊ 0⤋

8x-4y=16 where y = x-4
8x-4(2x-4)=16 -4 times 2x=8x and -4 times -4 = +16
8x-8x+16=16 8x - 8x = 0
16=16

2007-07-18 12:04:05 · answer #2 · answered by IRENE THE BOOKIE 3 · 0⤊ 0⤋

8x-4(2x-4)=16
8x-8x+16=16
0x=0
x=0

y=0-4
y=-4

2007-07-18 13:27:39 · answer #3 · answered by Dave aka Spider Monkey 7 · 0⤊ 0⤋