How do you solve this set of linear equations: #9x - 2y = 11; 5x - 2y = 15#?

1 Answer
Oct 9, 2016

Answer:

#x = -1 and y = -10#

Explanation:

#9x-2y = 11" and "5x -2y = 15#

Notice that there is #-2y"# in each of the equations.

Make #2y" " #the subject in each case.

#2y = 9x-11" and "2y = 5x-15#

#color(white)(xxxxxxxxx)2y = 2y#

#color(white)(xxxxx)9x-11 = 5x -15#

#color(white)(xxxxx)9x -5x =-15+11#

#color(white)(xxxxx.xxx)4x = -4#

#color(white)(xxxxxxxxx)x=-1#

#2y = 9x-11" "larr# substitute #-1 " for "x#

#2y = 9(-1)-11#

#2y = -9-11#

#y = -20/2#

#y = -10#