20x - 4y = -8
y = 2 + 5x
2007-07-22 12:14:49 · 7 answers · asked by shy31 2 in Science & Mathematics ➔ Mathematics
As you like.
Or even better, try both.
Hope get same results.
-
2007-07-22 12:16:51 · answer #1 · answered by oregfiu 7 · 2⤊ 0⤋
Substitution
20x - 4(2 + 5x) = -8
20x - 8 - 20x = -8
-8 = -8
maybe I did something wrong...
But if that's how it's supposed to be done than the system works.
2007-07-22 19:19:30 · answer #2 · answered by Sarbinargh 4 · 0⤊ 0⤋
since we know y=2+5x everytime u see y add 2+5x in its place
so
20x-4(2+5x)=-8
so simplfy by times -4 by 2+5x meaning -4*2 + -4*5x
so its
20x-8-20x=-8
now u have 0x-8=-8
so add 8 to each side
0x=0
x=0
then take x and put into one of the equations
y=2+5(0)
y=2+0
y=2
now check by putting x=0 and y=2 into both equations
20(0) -4(2)=-8
0-8=-8
-8=-8 YAY
2=2+5(0)
2=2+0
2=2 YAY
so x=0 y=2
good luck
2007-07-22 19:23:13 · answer #3 · answered by Mae-Day 3 · 0⤊ 0⤋
Subsitution
20x - 4(2+5x)= -8
20x - 8 -20x= -8
Can't be solved foer x because it gets cancelled out
2007-07-22 19:16:54 · answer #4 · answered by Swag 3 · 1⤊ 0⤋
0=0 undefined??
20x-4(2+5x)=-8
20x-8-20x=-8
20x-20x=-8+8
0=0
undefined
2007-07-22 19:23:01 · answer #5 · answered by Anonymous · 0⤊ 0⤋
this problem can't be solved because both equations are the same line.
In order to solve simultaneous equations, the lines have to be different and not parallel.
2007-07-22 19:28:21 · answer #6 · answered by David T 4 · 0⤊ 0⤋
I believe it is solvable either way, but I'd do substitution. It is the most direct, and reliable.
2007-07-22 19:21:54 · answer #7 · answered by Elizabeth K 2 · 0⤊ 0⤋