X-12y=-7 3x-6y=-21 how do I solve ?

1 Answer

Answer:

Use linear combination to eliminate one term in the equation.

Explanation:

The goal is to completely remove one variable from both sets of equations. The best way to do this is to combine both equations and manipulate them beforehand for elimination.

#x-12y=-7#
#(3x-6y=-21)xx2#

Multiply this equation by #2# so you have #12y# in both. Then, add/ subtract the equations from each other (choose the operation that will eliminate a variable, so in this case it is subtraction)

#x-12y=-7#
#6x-12y=-42" " " "# Subtract them straight down.

#-5x= 35#

#x= (-35)/5#

#x = -7#

Plug #x# into either equation to solve for #y#.

#-7 - 12y = -7#

#-12y = 0#

#y = 0#