Question

(x² + 4x - 21) ÷( x + 7)

Answer 1

Answer:

Consider the polynomial f(x)=x

2

+4x−21 and factorise it as follows:

f(x)=x

2

+4x−21=(x

2

+4x+4)−21−4=(x+2)

2

−25=(x+2)

2

−(5)

2

=(x+2+5)(x+2−5)

=(x+7)(x−3)

Therefore, f(x)=(x+1)(x−1)(x−3)

Let g(x)=x+7

Now divide f(x) by g(x) to get q(x):

q(x)=

(x+7)

(x+7)(x−3)

=x−3

Hence, the quotient is x−3.

Answer 2

Answer:

(x²+4x - 21 ) ÷ ( x+ 7)

= (4 x³- 21) ÷ (7x)

= 18 x³ ÷ 7x

= 2.571428 x²