Posted by **SAMMY** on Saturday, July 7, 2012 at 10:33pm.

Solve the following system of equations for the unknown variables.

a + b = 7

a + c = 12

b + c = 15

- MATH -
**Damon**, Sunday, July 8, 2012 at 12:20am
a + b = 7

a + c = 12

----------------subtract

b - c = - 5

then

b - c = -5

b + c = 15

----------- add

2 b = 10

b = 5

you take it from there

- MATH -
**Chima**, Sunday, July 8, 2012 at 11:20am
A+B=7, A=7-B---(1)

A+C=12,---(2), frm 1 substitute the value of A into eq 2 :7-B+C=12, C=12-7+B---(3)

also B+C=15---(4), also in the same way put C in eq3 into eq 4 ;B+12-7+B=15, B=5, now rem eq1 put B into it ;A=7-5=2 do the same thin 4 C by putin B in eq3 C=5

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