Solve x^2+6x+1=0 by completing the square
x2+6x+5=0 First of all half the x coefficient and write (x+6/2)2 the take away the (6/2)2 and add on the 5
(x+3)2-9+5=0
(x+3)2-4=0 Simplify the expression
(x+3)2=4 Move 4 to the other side of the equation so you can square root both sides
x+3=+-2 Take the square root of both sides
x=-5, x=-1 Take 3 away from both sides to find the 2 values of x that solve the equation
BS
Related Maths GCSE answers
All answers ▸What is the quadratic formula and how do I use it?
A cuboid of height 5 cm has a base of side 'a' cm. The longest diagonal of the cuboid is 'L' cm. Show that 'a' = SQRT[ (L^2 - 25)/2]
There are 35 people in a group. x(x+1) of them have a blue car, 5x of them have a red car, 4 have a blue and a red car and 4x-8 do not have car. Work out the probability that a person who has a blue car, has a red car as well.
Solve the following set of simultaneous equations: 3x + 2y = 15 & 9x + 4y = 1