SOLUTION: Hello, we are learning the substitution method of solving systems of equations. My equations are 4x + 5y = -6 and 2x - 10/3y = -4. I have tried it several different ways, and onc

Algebra ->  Expressions-with-variables -> SOLUTION: Hello, we are learning the substitution method of solving systems of equations. My equations are 4x + 5y = -6 and 2x - 10/3y = -4. I have tried it several different ways, and onc      Log On


   

Question 262796: Hello, we are learning the substitution method of solving systems of equations. My equations are 4x + 5y = -6 and 2x - 10/3y = -4. I have tried it several different ways, and once got (-6,18/5) and another time (0,6/5), neither of which is correct. Please show the steps so I can find my error. Thanks!!
Answer by drk(1908) About Me  (Show Source):
You can put this solution on YOUR website!
we have the following equations:
(i) 4x+%2B+5y+=+-6
(ii) 2x+-+%2810%2F3%29y+=+-4
step 1 - multiply (ii) by 3 to get
(iii) 6x+-+10y+=+-12
step 2 - multiply (i) by 2 to get
(iv) 8x+%2B+10y+=+-12
Notice that now, adding down with (iii) and (iv) we have y's drop out.
step 3 - add (iii) and (iv) together to get
(v) 14x+=+-24
divide and we get
x+=+-24%2F14
when reduced gives us
x+=+-12%2F7
now solve for y and we get
y+=+6%2F35