Quadratic formula ‘show that’ questions GCSE level 7

Simon Deacon

7 years ago

Quadratic formula questions …

… are usually something along the lines of:

solve 2x² – 5x – 6 = 0

and you are asked to ‘give your answer to 2 decimal places.’ This usually means that you will need to use the quadratic formula:

Here’s a link to a playlist with a number of different examples.

However you might also get questions asking you to ‘show that.’ These will still involve using the quadratic formula, but first you must show how an area or a volume can be calculated. Once you’ve demonstrated how to calculate, you’ll then apply the formula to work out the value of x.

Top Tips!

Keep track of how you are answering the question by working down the page
Remember to show all your working logically – particularly if you are calculating an area or volume
Make sure the equation is equal to zero before you factorise

If you’d like to ask for any more detail, or you’re not sure about anything, please do ask a question in the comments section.

Quadratic equations are very useful, with all sorts of applications. Here’s a link through to ‘what use is a quadratic equation,’ if you would like to read further.

All best with your studies.