Question

A polynomial expression is shown below.

Answer 1

Answer: m = -3

Step-by-step explanation:

The polynomial expression

(mx+8)(2x−4)

The next step is to expand the bracket

(mx × 2x) + (mx × -4) + (8×2x) + (8× -4)

2mx^2 - 4mx + 16x -32

2mx^2 - 4mx + 16x -32

2mx^2 + 12x -32 - - - - - - - - - - 1

From the question,

The expression is simplified to

−6x2+28x−32 - - - - - - - - - - - - 2

This means equation 1 = equation 2

Comparing both equations, we have

2mx^2 = −6x^2

2m = -6

m = -6/2 = -3

The correct option is a

The expression becomes

(-3x+8)(2x−4)

Let us check

Expanding the brackets,

(-3x × 2x) + (-3x ×-4)+ (8×2x) + (8×-4)

= -6x^2 +12x + 16x - 32

= -6x^2 +18x - 32