Solve the following system of linear equations by the addition method. If there is no solution or an infinite number of solutions, so state. Check your answer.
4x + 3y = 12
2x – 4y = 6
2006-10-02 14:33:58 · 7 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
To add the two equations, make the number of y's the same with a different sign.
Multiplying equation one by four and equation two by three:
16x +12y = 48
6x - 12y = 18
22x = 66
x = 3
so y = 0
check the answer:
4(3) + 3(0) = 12
12 + 0 = 12
2(3) - 4(0) =
6 - 0 = 6
2006-10-02 14:40:22 · answer #1 · answered by Steve A 7 · 0⤊ 1⤋
(1)=> 4x + 3y = 12
(2)=> 2x – 4y = 6
(1)=> 4x + 3y = 12
(2)*2=> 4x – 8y = 12
(1)-(2)=> 11y = 0 => y=0
Once you have one value for a variable, the rest is simple,
just substitute (1) with y value
(1) => 4x + 3y = 12
=> 4x = 12 - 3y
=> 4x = 12 - 3(0)
=> 4x = 12
=> x = 12/4 = 3
2006-10-02 21:47:49 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Double the second equation to get
4x + 3y = 12
4x - 8y = 12
So
11y = 0
y = 0, x = 3.
2006-10-02 21:55:31 · answer #3 · answered by steiner1745 7 · 0⤊ 0⤋
4x + 3y=12
2x-4y=6(-2)
4x + 3y=12
-4x+8y=-12
11y=0
no solution
2006-10-02 21:39:08 · answer #4 · answered by YouKnowMe 1 · 0⤊ 1⤋
divide the second one by 2
x-2y=3,
then x=3+2y
so going back to 1
4(3+2y)+3y=12
12+8y+3y=12
11y=0
y=0, so x=3+2(0)=3
2006-10-02 21:45:15 · answer #5 · answered by locuaz 7 · 0⤊ 0⤋
For what values of y would
3y = -12y ?????
Only one (null) answer ...
2006-10-02 21:39:04 · answer #6 · answered by lx470_98 1 · 0⤊ 1⤋
hey i don't mean to b rude but can't u do ur own homework with out haveing some one do it for u?
2006-10-02 21:37:27 · answer #7 · answered by AP 2 · 0⤊ 1⤋