Solve x^2+8x-5 = 0 by completing the square.

x2 + 8x = (x + 4)2 - 16, so x2 + 8x - 5 = (x + 4)2 - 16 - 5 = (x + 4)2 - 21, so then (x + 4)- 21 = 0 (x + 4)= 21 -----> x + 4 = √21 -------> x = -4 + √21                               x = -4 - √21

SJ
Answered by Shadab J. Maths tutor

11156 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

What is Pythagorus' Theorem?


Solve the simultaneous equations y = x + 3 and y = x^2 + 3x


Solve the following simultaneous equations: 1) 2x + 7y = 12 2) 4x = 14 - 4y


Write x^2+6x+14 in the form of (x+a)^2+b where a and b are constants to be determined.


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences