Question

Which expression is equivalent to (3x^2-7)?

A. (2x^2-11)-(x^2+4)
B. (5x^2-6)-(2x^2-1)
C. (10x^2-4)-(7x^2+3)
D. (15x^2-8)-(18x^2+1)

Answer 1

C.
`(10x^2-4)-(7x^2+3)`

Explanation:

In option A,

`(2x^2-11)-(x^2+4)= 2x^2 - 11 - x^2 - 4 = x^2 -15`

Since,

`(x^2-15)\\eq (3x^2-7)`

⇒ Option A is incorrect.

In option B,

`(5x^2-6)-(2x^2-1)= 5x^2-6-2x^2+1 = 3x^2 -5`

Since,

`(3x^2-5)\\eq (3x^2-7)`

⇒ Option B is incorrect.

In option C,

`(10x^2-4)-(7x^2+3)= 10x^2-4-7x^2-3 = 3x^2 -7`

⇒ Option C is correct.

In option D,

`(15x^2-8)-(18x^2+1)= 15x^2-8-18x^2-1= -3x^2 -9`

Since,

`(-3x^2 -9)\\eq (3x^2-7)`

⇒ Option D is incorrect.