SOLUTION: 9x+3y= -39 -9x+y = 71 y= 71+9x 9x+3(71+9x)= -39 9x+213+27x = -39 x= ? I know that the coefficient of x is 18 but then I forget how to solve for x

Algebra.Com
Question 232888: 9x+3y= -39
-9x+y = 71
y= 71+9x
9x+3(71+9x)= -39
9x+213+27x = -39
x= ?
I know that the coefficient of x is 18 but then I forget how to solve for x

Answer by Alan3354(69443)   (Show Source): You can put this solution on YOUR website!
9x+3y= -39
-9x+y = 71
y= 71+9x
9x+3(71+9x)= -39
9x+213+27x = -39
----------------
36x + 213 = -39
36x = -252
x = -7
-------
y = 71+9x = 71 - 63
y = 8
---------
***************
Elimination would have been easier for this one, since the coefficients of x are the same.
9x+3y= -39
-9x+y = 71
--------------
0x + 4y = 32
y = 8
----- etc


RELATED QUESTIONS

39>3-9x (answered by Alan3354)
9x +3y=-51,-5x +y=39 solve using substitution... (answered by JBarnum)
Please help me solve the linear system 9x - 7y = 31 -9x + 3y... (answered by macston)
ok so this is my equation. and i get it and all its just i cant get it to work but the... (answered by scott8148)
9x (answered by Edwin Parker)
9x (answered by Alan3354)
-27x^3y __________... (answered by checkley77)
9x = y X =... (answered by oscargut)
(9x^(3)y)/(27x^(5)y^(7)) (answered by jim_thompson5910)