How do you solve the system of equations #6x + 2y = 11# and #y = - 4x + 6#?

1 Answer
Mar 12, 2018

See a solution process below:

Explanation:

Step 1) Because the second equation is already solve for #y# we can substitute #(-4x + 6)# for #y# in the first equation and solve for #x#:

#6x + 2y = 11# becomes:

#6x + 2(-4x + 6) = 11#

#6x + (2 xx -4x) + (2 xx 6) = 11#

#6x + (-8x) + 12 = 11#

#6x - 8x + 12 = 11#

#(6 - 8)x + 12 = 11#

#-2x + 12 = 11#

#-2x + 12 - color(red)(12) = 11 - color(red)(12)#

#-2x + 0 = -1#

#-2x = -1#

#(-2x)/color(red)(-2) = (-1)/color(red)(-2)#

#(color(red)(cancel(color(black)(-2)))x)/cancel(color(red)(-2)) = 1/2#

#x = 1/2#

Step 2) Substitute #1/2# for #x# in the second equation and calculate #y#:

#y = -4x + 6# becomes:

#y = (-4 xx 1/2) + 6#

#y = -4/2 + 6#

#y = -2 + 6#

#y = 4#

The Solution Is:

#x = 1/2# and #y = 4#

Or

#(1/2, 4)#