Question

In the difference of (10x4 - 7x3 + 6x2) and (-3x2 + 4x4 - 8x3), if A, B and C are the coefficients of x⁴, x3 and x² respectively then what is the value of (2A + 3B - 5C)?
1. 38
2. -30
3. 26
4. -34

Answer 1

Correct Answer - Option 2 : -30

Calculation:

(10x4 - 7x3 + 6x2) - (-3x2 + 4x4 - 8x3)

⇒ (10x4 - 7x3 + 6x2 + 3x2 - 4x4 + 8x3)

⇒ 6x4 + x3 + 9x2

So,

A = 6

B = 1

C = 9

2A + 3B - 5C

⇒ 2(6) + 3(1) - 5(9)

⇒ 12 + 3 - 45

⇒ -30

∴ (2A + 3B - 5C) = -30

The correct option is 2 i.e. -30