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 ▸

How can I find the angle between 2 vectors?


What are simultaneous equations and how do I solve them?


Work out the gradient of the tangent to the curve (y=x^2-x-2) at the point where x=2


A right-angled triangle has an angle of 30 degrees and its hypotenuse has a length of 9cm. Find the length of either of the triangle's other two sides.