Factorise and solve x^2 - 8x + 15 = 0.
The easiest way to solve this problems it via trial and error. For any quatdratic (ax2 + bx + C = 0), the coeficcent of x, (in this case b = 8) is the sum(+) of the two solutions and c is the product(). So you need to find two numbers that add to give -8 and multiply to give 15. In this case it is -3 and -5 as -3+-5=-8 and -3-5=15. This measn the answer is (x-3)(x-5) = 0, so x= 3, or 5.
DM
Related Maths GCSE answers
All answers ▸How do I calculate the distance between two vectors?
How do I expand a factorised expression?
A quadrilateral has a perimeter of 42cm. Three sides have equal length and the fourth side is longer by 6cm. What is the length of the fourth side?
What is the area of triangle ABC where AB = 5 cm, BC = 12 cm and angle ABC = 50 degrees?