Question

If 2a + 7b+2c=16 and 2a + 3b +2c= 8, then b = ?

(A)-2
(B) O
(C) 2
(D) 4
(E) 6

Answer 1

(C) 2

Explanation:

Given equations 2a + 7b+2c=16 and 2a + 3b +2c= 8, you want to know the value of b.

Solution

The coefficients of 'a' and 'c' are the same in the two equations, so we can eliminate those variables by subtracting one equation from the other. We can keep the resulting coefficient of 'b' positive if we subtract the second equation from the first.

(2a +7b +2c) -(2a +3b +2c) = (16) -(8)

4b = 8 . . . . . . . simplify

b = 2 . . . . . . . divide by 4