Question

If a + b+ c = 5 , 3a + 2b + c = 7, 9a + 3b + c = 13 Find the value of a, b and c.

• A. a = 1, b = 3, c = 2
• B. a = 0, b = 3, c = 2
• C. a = 1, b = 0, c = 4
• D. a = 1, b = 2, c = 2

Answer 1

The correct option is C

a = 1, b = 0, c = 4

a + b + c = 5 ---------------------- (1)

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

9a + 3b + c = 13 ------------------ (3)

Multiply 3 in equation 1 and subtract equation 2 from it.

b + 2c = 8 -------------- (4)

Multiply 9 in equation 1 and subtract equation 3 from it

6b + 8c = 32 -------------- (5)

Solving equation 4 and 5

b = 0, c = 4

Substitute b and c in equation 1.

a + b + c = 5

a +0 + 4 =5

a = 1

So, a = 1, b = 0 and c = 4