How to complete the square to solve quadratic equations?
Equation: x2 +4x-5=0 (This is in the form ax2+2bx+c=0)First divide 2b by 2 (4/2=2)Then put this into (x+b)2-(b)2+c=0This gives: (x+2)2-(2)2+ -5=0 (remembering +and- makes a -)Simplify to: (x+2)2-9=0Move the 9 across: (x+2)2=9Square root both sides: x+2=+-3 (remembering the plus and minus roots)Then take away 2 from both sides to give: x= -2+-3And the two values for x now are 1 and -5
GJ
Related Maths GCSE answers
All answers ▸Solve (5-x)/2= 2x-7
The diagram shows a prism. The cross-section of the prism is an isosceles triangle. The lengths of the sides of the triangle are 13 cm, 13 cm and 10 cm. The perpendicular height of the triangle is 12 cm. The length of the prism is 8 cm. Work out the total
How to factorise quadratic equations?
Factorise the following expression x^2+11x+24=0