SOLUTION: solve by the elimination method 7r-8s=-21 8r+7s=89 a.the solution is? b.there are infinitely many solutions c.there is no solution

Algebra.Com
Question 420710: solve by the elimination method
7r-8s=-21
8r+7s=89
a.the solution is?
b.there are infinitely many solutions
c.there is no solution

Answer by mananth(16946)   (Show Source): You can put this solution on YOUR website!
7r-8s =-21 .............1
8r+7s= 89 .............2

multiply (1)by 7
Multiply (2) by 8
49 r + -56 s = -147
64 r + 56 s = 712

Add the two equations

113 r = 565

/ 113

r = 5

plug value of r In (1)

7 r + -8 s = -21
35 + -8 s = -21
-8 s = -21 + -35
-8 s = -56
s = 7

RELATED QUESTIONS

Solve by the elimination method. 3r-7s=-35 7r+3s=73 If necessary what is the... (answered by ankor@dixie-net.com)
solve by the elimination method. 4x+5y=2 8x+10y=4 a.the solution is? b. there are (answered by Mr. Math Wiz)
Solve by the elimination method. 7a+9b=22 -7a+b=18 The solution is __? There are... (answered by josgarithmetic)
use the method of elimination to solve the system of linear equations. 3a = 7 - b 3a... (answered by MathLover1)
Use the elimination method to solve the system of equations. a+7b=15 a+4b=6 These... (answered by jim_thompson5910)
Use the elimination method to solve the system of equations a+9b=22 a+4b=7 A.... (answered by tanjo3)
Solve by the elimination method. 7x+9y=44 5x-9y=92 What is the solution of the... (answered by jorel1380)
Solve the system of equations by the addition method. { 4x = 5y =5 { 16x - 20y =10 (answered by MathLover1)
Solve the system by either substitution or the elimination method, if possible. (If there (answered by ichigo449)