using the substitution method 5x +7y = -1 -6x + y = 20
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What are you having trouble with, just eliminate one of the variables and solve for the other.
Originally Posted by mathdummy22 using the substitution method 5x +7y = -1 -6x + y = 20 Solve the second equation for y. $\displaystyle y=6x+20$ Substitute 6x+20 for y in the first equation and solve for x. Once you have x, you can use either equation to find y.
i get x = -139/47 and y= 106/47..... I have no clue what Im doing wrong
5x +7y = -1 -6x + y = 20 y = 6x+20 7y = 42x +140 5x+42X+140 =-1 Here is where you screw up. 47x = -141 x = -3 y = 2 by substitution.
Solve the second equation for y. $\displaystyle y=6x+20$ Substitute back into 1st equation: $\displaystyle 5x+7(6x+20)=-1$ $\displaystyle 5x+42x+140=-1$ $\displaystyle 47x=-141$ $\displaystyle x=-3$ Now solve for y using $\displaystyle y=6x+20$
Originally Posted by terr13 5x+42X+140 =-1 Here is where you screw up. When I screw something up, I always try to screw it back down.
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