SOLUTION: How do I solve by using a system of two equations in two variables? Jennifer is 6 years older than Sue. In 4 years, she will be twice as old as Sue was 5 years ago. Find their

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Question 141360This question is from textbook Prentice hall algebra 1
:
How do I solve by using a system of two equations in two variables?
Jennifer is 6 years older than Sue. In 4 years, she will be twice as old as Sue was 5 years ago. Find their ages now. This question is from textbook Prentice hall algebra 1

Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
set up the following equation:
J=S+6 THIS SAYS JENNIFER IS 6 YEARS OLDER THAN SUE.
J+4=2(S+6-5) THIS EQUATION SAYS THAT IN 4 YEARS (J+4)JENNIFER = (WILL BE) 2 TIMES AS OLD AS SUE WAS 5 YEARS AGO 2(S+6-5).
NOW SOLVE FOR S BY SUBSTITUTING (S+6) FOR J IN THE SECOND EQUATION.
(S+6)+4=2(S+6-5)
S+6+4=2(S+1)
S+10=2S+2
S-2S=2-10
-S=-8
S=8 SUE'S AGE NOW.
J=8+6=14 JENNIFER'S AGE NOW.
PROOF:
14+4=2(8+6-5)
18=2(9)
18=18