Expand and simplify 4(x+5) + 3(x-7)

When we're doing algebra and expanding brackets, our first step is to multiply everything inside each bracket by what we have just before the bracket. Let's start with the 4(x+5). 4 lots of our unknown mystery number x would give us 4x. 4 lots of 5 gives us 20. So together we have 4x + 20. Doing the same for 3(x-7), 3 lots of x gives us 3x. 3 lots of -7 gives us -21. So all together we have 3x-21. Putting both parts together we have 4x + 20 + 3x - 21. Now we need to simplify this. If we write this in a different order with our x's together and our integers (or whole numbers) together we have 4x + 3x + 20 - 21. From here we can see we have 7x - 1. And there's our final answer.

CM

Related Maths GCSE answers

All answers ▸

There are 7 blue pens, 4 green pens and 6 red pens in a box. One pen is taken at random from the box. Write down the probability that this pen is blue


2017 Edexcel Summer 2017 Q18) 16^1/5 × 2^x = 8^3/4 Work out the exact value of x


Solve the inequality x^2+2x-8<0


Factorise f(x) = x^2+4x+4 and sketch the curve, identifying the roots and minimum point of f(x).