SOLUTION: I need to help using the substitution method for 9x+4y=-32 x=1-5y any help would be great

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Question 198335: I need to help using the substitution method for
9x+4y=-32
x=1-5y
any help would be great
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
9x%2B4y=-32 Start with the first equation.


9%281-5y%29%2B4y=-32 Plug in x=1-5y into the first equation. In other words, replace each x with 1-5y. Notice we've eliminated the x variables. So we now have a simple equation with one unknown.


9-45y%2B4y=-32 Distribute


-41y%2B9=-32 Combine like terms on the left side


-41y=-32-9Subtract 9 from both sides


-41y=-41 Combine like terms on the right side


y=%28-41%29%2F%28-41%29 Divide both sides by -41 to isolate y



y=1 Divide




Now that we know that y=1, we can plug this into x=1-5y to find x


x=1-5y Start with the second equation


x=1-5%281%29 Plug in y=1


x=1-5 Multiply


x=-4 Subtract


So our answers are x=-4 and y=1 which form the ordered pair



Notice if we graph the two equations, we can see that their intersection is at . So this verifies our answer.


+graph%28+500%2C+500%2C+-5%2C+5%2C+-5%2C+5%2C+%28-32-9x%29%2F4%2C+%28x-1%29%2F%28-5%29%29+ Graph of 9x%2B4y=-32 (red) and x=1-5y (green)