# 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

Algebra ->  Algebra  -> Systems-of-equations -> 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      Log On

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 Algebra: Systems of equations that are not linear Solvers Lessons Answers archive Quiz In Depth

 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. ------------------------ 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. ------------- Multiply by 3 to eliminate fractions 67y = -133 y = -133/67 ------------- 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 ```