SOLUTION: y=4x+11 -6x+8y=36 solving systems by substitution ??????? Help please !!!!!

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Question 124877This question is from textbook algebra I
: y=4x+11
-6x+8y=36
solving systems by substitution ??????? Help please !!!!! This question is from textbook algebra I

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
Start with the given system
-6x%2B8y=36
y=4x%2B11



-6x%2B8%284x%2B11%29=36 Plug in y=4x%2B11 into the first equation. In other words, replace each y with 4x%2B11. Notice we've eliminated the y variables. So we now have a simple equation with one unknown.


-6x%2B32x%2B88=36 Distribute


26x%2B88=36 Combine like terms on the left side


26x=36-88Subtract 88 from both sides


26x=-52 Combine like terms on the right side


x=%28-52%29%2F%2826%29 Divide both sides by 26 to isolate x



x=-2 Divide




Now that we know that x=-2, we can plug this into y=4x%2B11 to find y



y=4%28-2%29%2B11 Substitute -2 for each x


y=3 Simplify


So our answer is x=-2 and y=3 which also looks like



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+%2836%2B6x%29%2F8%2C+4x%2B11%29+ Graph of -6x%2B8y=36 (red) and y=4x%2B11 (green)