x^2+2=18, find the value of x.
This is a basic rearranging of the equation that easily catches students out and will generally be offered 3 marks. The first thing to do is take the 2 on the other side of the equation so we get x^2=16. From this points all we have to do is take root of 16. However what students easily forget is that there are always 2 roots of positive numbers one being the original root and one being its negative counterpart. Experienced students should remember this and thus get the answer that x=4 or x=-4.
IP
Related Maths GCSE answers
All answers ▸Solve the equation: x^2+x-12=0
Derive the quadratic formula form the general quadratic equation
Expand and simplify (x-2)(2x+3)(x+1)
One of the teachers at a school is chosen at random. The probability that this teacher is female is 3/5. There are 36 male teachers at the school. Work out the total number of teachers at the school.