SOLUTION: Solve each system of equations by using substitution. {{{ 8x + 9y = 9 }}} {{{ 3x - 5y = 20 }}} I've multiplied the bottom equation by 3 and got 9x

Question 477473: Solve each system of equations by using substitution.

I've multiplied the bottom equation by 3 and got 9x - 15y = 60, but it isn't going to be correct because 8x - 9x = -x so the x hasn't been eliminated. I don't know what to do about it. The rest of the problem made no sense because the numbers were too high after I plugged them in. I got -x + -6 = -51 then divided that by -6 which got me 8.5. I didn't know what to do with the -x so I just ignored it bu I don't think that's right. Any solutions?
Found 2 solutions by Alan3354, ewatrrr:
Answer by Alan3354(30993) (Show Source):
You can put this solution on YOUR website!
Solve each system of equations by using substitution.

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You have to solve one of the eqns for x or y, then sub into the other eqn.
Substitution is not the best method for these 2, but sometimes you don't get to choose.

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Multiply by 3 to eliminate fractions

67y = -133
y = -133/67
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Sub for y in either eqn and find x

x = (-665/67 + 1340/67)/3
x = 225/67

Answer by ewatrrr(10682) (Show Source):
You can put this solution on YOUR website!

Hi,
Solve each system of equations by using substitution.
using Substitution
8x + 9y = 9 OR y = (-8/9)x + 1
3x - 5[(-8/9)x + 1] = 20
3x + 40/9x - 5 = 20
27x + 40x - 45 = 180
67x = 225
x = 225/67 and y = (-8/9)225/67 + 1 = -1.9851
using Elimination
8x + 9y = 9
27/5x - 9y = 36 |Recommend multiplying thru with 9/5 to eliminate y
67/5x = 45
x = 225/67 etc

SOLUTION: Solve each system of equations by using substitution. {{{ 8x + 9y = 9 }}} {{{ 3x - 5y = 20 }}} I've multiplied the bottom equation by 3 and got 9x - 15y = 60, but it i