Question

If a-b=10 and a+b=31 what is the value of 3a-2b

Answer 1

a - b = 10

a + b = 31

(a - b) + (a + b) = 10 + 31

2a = 41

a = 41/2

41/2 - b = 10

b = 21/2

3a - 2b = 3(41/2) - 2(21/2) = 81/2