Question

factorise x²+3x-28​

Answer 1

Answer:

Explanation:

We can Split the Middle Term of this expression to factorise it.

In this technique, if we have to factorise an expression like

ax2+bx+c

, we need to think of 2 numbers such that:

N1⋅N2=a⋅c=1⋅−28=−28

and

N1+N2=b=−3

After trying out a few numbers we get

N1=−7 and N2=4

7⋅−4=−28 , and 4+(−7)=−3

x2−3x−28

=x2−7x+4x−28

=x(x−7)+4(x−7)

=(x+4)(x−7)

Answer 2

x^2 + 3x - 28

-28 can be factorised as -7 x 4

identity is x^2 + (a+b)x + ab = (x+a) (x+b)

= x^2 + (7-4)x + (-7 x 4)

so the ans ....becomes

(x+4) (x-7)

hope it helps you✌