Solve, using the quadratic formula, the equation x^2 +2x=35

suppose you have a general quadratic equation in the form ax2 + bx + c = 0, then the solutions to this quadratic equation can be found by the equation x = (-b +/- (b2-4ac)1/2)/2aThe 'plus or minus symbol' is because a quadratic equation can give you up to two real solutions. One of which can be found by putting a plus here and the other by putting a minus here. Therefore we get two equations which you can then solve to find the two values of x:x= (-b + (b2- 4ac)1/2)/2a and x= (-b - (b2- 4ac)1/2)/2aFor the equation x2+2x=35, we need to first write this in the form ax2 + bx + c = 0. We can do this by subtracting 35 from both sides, giving: x2+2x-35 = 0, then, finding our values of a, b and c, we get a=1, b=2 and c=-35.Substituting these values into our two equations for x, we get:x= (-(2) + ((2)2- 4(1)(-35))1/2)/2(1) and x= (-(2) - ((2)2- 4(1)(-35))1/2)/2(1)simplifying these equations gives:x= (-2 + (4- (140))1/2)/2 and x= (-2 - (4- (140))1/2)/2further simplification gives:x= (-2 + 12)/2 and x= (-2 + 12)/2therefore we get the answers x=5 and x=-7

AS
Answered by Antonia S. Maths tutor

4029 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

3 teas and 2 coffees have a total cost of £7.80; 5 teas and 4 coffees have a total cost of £14.20. Work out the individual cost of one tea and one coffee.


How do I know which trig formula to use in the exam?


Using your knowledge that tan(x) = sin(x) / cos(x) , how would you write 4/7tan(x)


I have invested £10000 for 5 years and I how have £12763 in my account. What is my banks interest rate?


We're here to help

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

MyTutor is part of the IXL family of brands:

© 2026 by IXL Learning