Question

Solve the system of linear equations. separate the x- and y- values with a coma. -8x=72-16y

Answer 1

Let's use the "elimination by addition/subtraction" method to solve this system for x and y.

 -8x=72-16y             
4x=-92+16y        <= Mult. all 3 terms by 2:          8x = - 184 + 32y

Now combine the following, column by column:

 -8x=       72-16y
8x = - 184 + 32y
-----------------------
   0 = -112 + 16y.  Solving for y, 16y = 112, and y = 7.

Now subst. 7 for y in either of the original equations and calculate x:

4x=-92+16(7)   =>   4x = -92 + 112  =  20.  Then x = 5.

Solution is 5, -7   (or, better written) (5, - 7).