How do you solve the system by substitution for #–4.5x -2y=– 12.5# and #3.25x – y=– 0.75#?

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Answer 1 · 2015-03-28T10:35:53

The answer is:

#x=1#
#y=4#.

Because:

#–4.5x -2y=– 12.5#
#3.25x – y=– 0.75#

Form the second equation, let's find #y#, than let's substitue in the first:

#y=3.25x+0.75#

and so:

#-4.5x-2*(3.25x+0.75)=-12.5rArr#

#-4.5x-6.50x-1.5=-12.5rArr-11x=-11rArrx=1#.

And now let's go back:

#y=3.25*1+0.75rArry=4#.