Factorise (5x^2 + 7x + 2)

This expression is in the form of ax^2 + bx + c, so you need to find two numbers which multiply to get ac and add to make b.
Step 1: Here a is not = 1, so you need to take out the highest common factor. In this case, the HCF is 1, so we keep the expression as it is.
Step 2: Identify the product (ac) and the sum (b). When ax^2 + bx + c is (5x^2 + 7x + 2) then ac is 5 x 2 = 10 and b is 7
Step 3: Find the numbers which multiply to make 10 (ac) and add to make 7 (b), in this case:5 x 2 = 10 and 5 + 2 = 7
Step 4: Re-write the expression, replacing bx with the numbers from Step 35x^2 + 5x + 2x + 2
Step 5:Divide this expression into two groups: (5x^2 + 5x) and (2x + 2)and factor out the highest common factor of both:5x(x + 1) and 2(x + 1)
Step 6:Now, take out the common factor, in this case (x+1). The other bracket will be the leftover values, in this case (5x + 2).
So your answer is: (5x + 2)(x+1).Use F.O.I.L to check your answer.



DJ

Related Maths GCSE answers

All answers ▸

Factorise x^2+3x+2=0


Solve algebraically the simultaneous equations: x^2+y^2 = 25 and y-3x=13


How do you divide fractions and mixed numbers


c) Sharon is organising an event. The tickets cost 12 pounds each. Sharon paid 200 pounds for the cost of the event. How many tickets will Sharon have to sell to make a profit? (2 marks)