SOLUTION: Hi, I am having trouble with the following question, ant help would be gratefully received. Kind regards, Hugh Factorise the following expressions. Question A (

Question 836899: Hi,
I am having trouble with the following question, ant help would be gratefully received.
Kind regards,
Hugh
Factorise the following expressions.
Question A
(i) x2 − x − 42
(ii) 9m2 − 81n2
Question B
In parts (i), (ii) below you should include each step in your
reasoning and check that your solution is correct.
(i) Factorise then solve the equation x2 + 2x−24 = 0.
(ii) Explain how you could use your answer to part (B)(i) to solve the
equation 7x2 + 14x−168 = 0.

Found 2 solutions by josgarithmetic, LinnW:
Answer by josgarithmetic(39617) (Show Source): You can put this solution on YOUR website!
The same question for (i) and (ii) in "question A" was answered one or two days ago.

(i) Use the integers, 6 and 7.
+6-7=-1

(ii) This is the difference of squares so the factorization is based on the formula,

Question B
Each term in (ii) contains a factor of 7.
This is .
Look then at the factorizations for -24=-1*6*4 and you should be able to factor the quadratic expression.

Answer by LinnW(1048) (Show Source): You can put this solution on YOUR website!
Factorise the following expressions.
Question A
(i) x2 − x − 42
(ii) 9m2 − 81n2
Question B
In parts (i), (ii) below you should include each step in your
reasoning and check that your solution is correct.
(i) Factorise then solve the equation x2 + 2x−24 = 0.
(ii) Explain how you could use your answer to part (B)(i) to solve the
equation 7x2 + 14x−168 = 0.
A(i)
We want a pair of numbers such that their product is 42 and
their sum is -1
-7 and + 6 work for this and factored is
(x - 7)(x + 6)
A(ii)
Binomials of the form factor as
so think of as
which means the factors are
(3m+9n)(3m-9n)
B(i) x2 + 2x−24 = 0.
Here we want a pair of numbers whose product is -24 and their sum is +2
+6 and -4 work for this
(x + 6)(x - 4) = 0
B(ii)
(ii) Explain how you could use your answer to part (B)(i) to solve the
equation 7x2 + 14x−168 = 0.
7 is a factor of each term, so 7x2 + 14x−168 = 0 factored is

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