Question 32277
2C+B=3*7.00
3C+2B=5*6.90 MULTIPLY FIRST EQUATION  BY -2 WE GET

-4C-2B=-2*21.00 ADDING THIS TO THE SECOND EQUATION 
3C+2B=34.50 WE GET
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-C=-42.00+34.50 OR C=7.50 SUBSTITUTING THIS IN THE FIRST EQUATION WE GET

2*7.50+B=21.00 OR 15.00+B=21.00 OR B=21.00-15.00 OR B=6.00

PROOF 3*7.50+12.00=34.50 OR 22.50 +12.00=34.50 34.50=34.50