How do you solve the system of equations #8a - 5b = 5# and #16a + 7b = 129#?

1 Answer
Anjali G
Nov 22, 2016

#a=5#
#b=7#

Explanation:

#8a-5b=5#
#16a+7b=129#

Multiply the first equation by -2 to use elimination:
#-2(8a-5b)=-2(5)#
#-16a+10b=-10#

Add the two equations:
#16a+7b=129#
#-16a+10b=-10#

#17b=119#
#b=7#

Substitute #b=7# into one of the original equations:
#8a-5b=5#
#8a=5b+5#
#a=1/8(5b+5)#
#a=1/8(5(7)+5)#
#a=5#

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