Question

Which of the following cannot be solved using the quadratic formula?

Answer 1

A.
`-3x^(2)-x+3=-3x^(2)`

Explanation:

We know that,

The quadratic formula is used to find the solution of a quadratic equation
`ax^(2)+bx+c=0` i.e. an equation of degree 2.

Now, in option A, we have,

`-3x^(2)-x+3=-3x^(2)` i.e.
`-x+3=-3x^(2)+3x^(2)` i.e.
`-x+3=0`

So, the final equation is not a quadratic equation but it is a linear equation.

Hence, for this equation, we cannot use the quadratic formula.

Answer 2

Option A is correct, i.e. -3x² -x +3 = -3x²

Explanation:

We can rearrange the terms, and combine like terms to get each equation in standard form of quadratic equation like ax²+bx+c=0.

It must have degree 2 to be solved using quadratic formula.

Option A: -3x² -x +3 = -3x²

Rearranging the terms:-

3x² -3x² -x +3 = 0

Combining like terms:-

0 -x +3 = 0

-x +3 = 0

This is linear equation with degree 1 and can be solved without quadratic formula.

Hence, option A is correct, i.e. -3x² -x +3 = -3x²