Expand and simplify (x+4)(x-5).
For this, we use the FOIL method of expanding brackets; start by multiplying the FIRST terms of each bracket together to get xx=x^2. Next multiply the OUTSIDE elements, ie the first element in the first bracket and the last in the second, giving x(-5)=-5x. Then comes the INSIDE elements, giving 4x=4x, and finaly the LAST elements of each bracket, giving 4(-5)=-20. Adding all these terms together gives us our answer; x^2+4x-5x-20, which can be simplified to x^2-x-20.
AJ
Related Maths GCSE answers
All answers ▸Billy wants to buy 10kg of the same oranges. Type A comes in bags of 1.25 kg and costs £1.50. Type B comes in bags of 5kg and used to cost £6.60 but are now 15% off. Which type is more worth it for Billy and how much does it cost?
Solve algebraically the simulations equations: x^2+y^2=25 and y-3x=13
Nicky buys a blender. 20% VAT is added to the price of the blender so Nicky has to pay £180. What is the price of the blender with no VAT added?
Solve 7x=4(x-8)