Solve the system of equations by the addition method. If the system does not have a single ordered pair as a solution, state whether the system is inconsistent or dependent.
-5x + 7y = -40
-2x + 4y = -16
(8, 0)
No solution, inconsistent
(7, 1)
(8, 1)
2007-07-03 14:34:52 · 3 answers · asked by alw0322 1 in Science & Mathematics ➔ Mathematics
Multiply the bottom equation by -2.5 and add:
-5x + 7y = -40
+ (5x -10y)= 40
--------------------------
-3y = 0
So Y=0
Plug y=0 into the first equation and solve:
-5x=-40
x=-40/-5
x=8
Now plug y=0 and x=8 into the second answer to confirm.
-2(8)=-16
-16=-16
CHECK
Your answer is (8,0).
2007-07-03 14:47:04 · answer #1 · answered by Anonymous · 0⤊ 0⤋
-5x + 7y = -40 multiply both sides by 2
-10x+14y=-80
-2x + 4y = -16 multiply both sides by -5
10x-20y=80
-10x+14y=-80 add to equation above
34y=0
y=0
-2x+4y=-16 substitute 0 for y
-2x=-16 divide both sides by -2
x=8
(8, 0) is the answer
2007-07-03 23:50:33 · answer #2 · answered by yupchagee 7 · 0⤊ 0⤋
10x - 14y = 80
- 10x + 20y = -80----ADD
6y = 0
y = 0
-5x = - 40
x = 8
Solution is x = 8 , y = 0
2007-07-07 12:31:06 · answer #3 · answered by Como 7 · 0⤊ 0⤋