SOLUTION: Please help me solve this linear system: x+7=-9y y=7-4x I need to figure out what x and y is.. Thank you.

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Question 253241: Please help me solve this linear system:
x+7=-9y
y=7-4x
I need to figure out what x and y is..
Thank you.
Found 3 solutions by ankor@dixie-net.com, jim_thompson5910, drk:
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Please help me solve this linear system:
x+7=-9y
y=7-4x
:
Use the 2nd equation: substitute for y in the 1st equation
x + 7 = -9(7-4x)
x + 7 = -63 + 36x
7 + 63 = 36x - x
70 = 35x
x = 70%2F35
x = 2
:
Find y using the 2nd equation
y = 7 - 4(2)
y = 7 - 8
y = -1
;
Check solutions in the 1st equation
2 + 7 = -9(-1)
9 = 9

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
x%2B7=-9y Start with the first equation.


x%2B7=-9%287-4x%29 Plug in y=7-4x


x%2B7=-63%2B36x Distribute.


x=-63%2B36x-7 Subtract 7 from both sides.


x-36x=-63-7 Subtract 36x from both sides.


-35x=-63-7 Combine like terms on the left side.


-35x=-70 Combine like terms on the right side.


x=%28-70%29%2F%28-35%29 Divide both sides by -35 to isolate x.


x=2 Reduce.


y=7-4x Go back to the second equation.


y=7-4%282%29 Plug in x=2


y=7-8 Multiply


y=-1 Subtract


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Answer:

So the solutions are x=2 and y=-1 giving us the ordered pair (2,-1)

Answer by drk(1908) About Me  (Show Source):
You can put this solution on YOUR website!
Our 2 original equations are:
(i) x+7=-9y
(ii) y=7-4x
I will use substitution for this. Put (ii) in for the y in (i) as
(iii) x + 7 = -9 (7-4x)
distribute the-9 as
(iv) x + 7 = -63 + 36x
isolate x and the number as
(v) 70 = 35x
x = 2. since x = 2, we find y = -1.
(2, -1)