Question

factorise the following: x 2 +5x−84​

Answer 1

Answer:

-12 or 7

step by step explaination .

choose the numbers which product is -84 and their addition is +5....

factors is 12 and -7 .....because their product is -84 and addition is 5.....

so solve ny using factorization method we get answer -12 and 7...

hope this will help you.....

Answer 2

Factors are $\bf \red{{x}^{2} + 5x - 84 =(x - 7)(x + 12) }$

Given:

• ${x}^{2} + 5x - 84$

To find:

• Factors of quadratic polynomial.

Solution:

Concept to be used:

A standard quadratic polynomial is given by $a {x}^{2} + bx + c \:$, where a≠0.

In factorisation using split the middle term.Split b like that the multiplication of parts equal to ac.

Step 1:

Here,

b= 5x

Multiplication of ac= -84x²

So,

$5x = 12x - 7x$

And

$(12x)( - 7x) = - 84 {x}^{2}$

Step 2:

Factorise the polynomial.

${x}^{2} + 5x - 84 = {x}^{2} + 12x - 7x - 84$

or

${x}^{2} + 5x - 84 =x(x + 12) - 7(x + 12)$

or

${x}^{2} + 5x - 84 =(x - 7)(x + 12)$

Thus,

Factors are $\bf {x}^{2} + 5x - 84 =(x - 7)(x + 12)$

Learn more:

1) find the value of x in the quadratic equation (2x-4)^2=64

https://brainly.in/question/25116413

2) √3x²+11×+6√3 please do it

https://brainly.in/question/11839