Question 1106880: how do i solve this by substitution: 5x+2y=9
y=-x-3 and how do i solve it bye graphing
Found 2 solutions by josgarithmetic, stanbon:
Answer by josgarithmetic(39617)   (Show Source):
You can put this solution on YOUR website! You just substitute one variable's formula for the other.
You already have a formula for y. Use the expression in the first equation.
YOU DO IT! Solve for x. Finish.
Just solve both equations for y in terms of x and use slope and y-intercepts to graph and find the intersection point.
Read it as well as you can. Try on paper if you want (graph PAPER).
Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website! solve this by substitution: 5x+2y=9 ; y=-x-3
5x+2(-x-3) = 9
5x-2x-6 = 9
3x = 15
x = 5
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y = -x-3 = -5-3 = -8
Ans:: (5,-8)
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and how do i solve it by graphing
graph y = -x-3
If x = 0, y = -3
If x = -3, y = 0
Plot (0,-3) and (-3,0) and draw a line thru them.
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graph 5x+2y = 9
y = (-5x+9)/2
If x = 0, y = 9/2
If x = 1/5, y = 4
Plot (0,4.5) and (1/5,4) and draw a line thru them.
The lines intersect at (5,-8)
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Cheers,
Stan H.
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