Solve x^2+4x-5=0

Two approaches.1.Note that the equation is a quadratic equation, and can thus be solved per the quadratic formula, in which the solutions are given to be (-b+-sqrt(b^2-4ac))/2a.Plugging in the values from the quadrartic, one obtains (-4+-sqrt(36))/2, i.e. x equals 1 and -5.2.Solve by collecting terms and expressing in the form (ax+b)(cx+d)=0. One notices that the following must hold.cd=-5ad+cb=4ac=1While the former approach is generally easier, as many students will try the latter with trial and error, the latter yields nice numbers in this instance: (x+5)(x-1)=0. The solutions to the quadratic occur when the RHS=LHS, i.e. when one of the brackets evaluates to 0. Therefore, one obtains x equals -5 and 1.

Answered by Samuel H. Maths tutor

3227 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

Make x the subject of the formula 4(2x-y) = 3ax - 5


Draw the graph y=tanx in the region -180 degrees =< x =< 180 degrees


Solve 5x^2 - 9x + 4 = 0 using the quadratic formula


Work out the ratio between the surface area of sphere of radius 6cm and the total surface area of a hemisphere of radius 9cm.


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2024

Terms & Conditions|Privacy Policy
Cookie Preferences