7a+7b=11 and -7a+b=10

Question

solve by elimination method 7a+7b=11 and -7a+b=10

Answer 1

7a+7b=11 and -7a+b=10
solve by elimination method 7a+7b=11 and -7a+b=10

    7a + 7b = 11
+(-7a +   b = 10)
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            8b  = 21
8b = 21
b = 21/8

-7a + b = 10
-7a + 21/8 = 10
-7a = 10 - 21/8
-7a = 80/8 - 21/8
-7a = 59/8
a = (59/8) * (-1/7)
a = -59/56

Check.....

-7a + b = 10
-7(-59/56) + 21/8 = 10
59/8  + 21/8 = 10
80/8 = 10
10 = 10

a = -59/56 and b = 21/8