Solve the equation x^2 + 8x = -15

We first notice it's a quadratic equation in x so we want to make one side of the equation equal to 0.By adding 15 to both sides we get : x2 + 8x + 15 = 0We then look for two numbers which multiply to 15 and add to make 8 to help us factorise the LHS . The numbers are 3 and 5 so the equation becomes: (x+3)(x+5) = 0Therefore either x + 3 = 0 so x1 = -3or x + 5 = 0 so x2 = -5

Answered by Georgina L. Maths tutor

2862 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

How do you work out the surface area of a cylinder?


Dipen and Nisha are planning a wedding reception. Nisha says, “I want to invite 70 guests.” Dipen says, “If we invite one-fifth fewer guests, we will save more than £500” Is Dipen correct?


There is a bag of blue, red, and white counters. 1/6 of the bag is blue counters. 1/4 of the bag is red counters. What is the smallest number of white counters that could possibly be in the bag.


Solve the simultaneous equations: 3x + 2y = 4 and 4x + 5y = 17


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 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences