Question

Factor x2 – 3x – 28. Identify the values that should be written to complete the X diagram. On the top: On the bottom: On the sides: Rewrite the expression using the numbers on the sides of the X diagram. Use double grouping to factor the four terms. x2 – 3x – 28 =

Answer 1

x2 – 3x – 28 = (x-7)(x+4)

Answer 2

Answer:

The factor form of given expression is $(x-7)(x+4)$.

Step-by-step explanation:

The given expression is

$x^2-3x-28$

$x^2-7x+4x-28$

$x(x-7)+4(x-7)$

$(x-7)(x+4)$

Therefore the factor form of given expression is $(x-7)(x+4)$.

If a expression is in the form of $ax^2+bx+c$, then in X diagram ac is written on the top, b is written on the bottom and the required factors of ac are written on the sides.

In the given expression,

$a=1$

$b=-3$

$c=-28$

$ac=1\times -28=-28$

The X diagram is shown in the given figure.

Therefore the factor form of given expression is $(x-7)(x+4)$.