Calculate (7 + √3)(7 - √3)

(7 + √3)(7 - √3) = 72 + 7√3 - 7√3 - (√3)2 = 49 - 3 = 46Alternatively you can go straight to identifying that this is the difference between two squares, using the fact that (a + b)(a - b) = a2 - b2

IB

Related Maths GCSE answers

All answers ▸

A house increases by 25% to £80,000. Find what it was worth before the rise.


How do I factorise this expression? [Let’s say it’s x^2 + 5x + 6]


Where do the lines 2y = 4x + 2 and - 3x + y = 4 intersect?


Solve the simultaneous equations 5x + y = 21, and x - 3y = 9.