Does the equation: x^2+5x-6 have two real roots? If so what are they?

Having two real roots is equivalent to having two intersections with the x axis.

The equation is a parabola (a U shape) so, having two real roots is equivalent to having the lowest point of the curve below the x axis.

By differentiation we have that 2x+5 is the rate of change, and setting this equal to zero gives the stationary point x=-5/2.

Using the equation we then have:

y=(-5/2)2+5(-5/2)-6=-12.25

This shows that the minimum point of the curve is (-5/2,-12.25) which is below the x axis.

Thus, there are two real roots and applying the quadratic formula gives the values: -6 and 1.

Where the quadratic formula is:

[-b+sqrt(b2-4ac)] / [2a] and [-b-sqrt(b2-4ac)] / [2a]

SB
Answered by Stephen B. Maths tutor

5706 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

Given that (cos(x)^2 + 4 sin(x)^2)/(1-sin(x)^2) = 7, show that tan(x)^2 = 3/2


write 2(sin^2(x)- cos^2(x)) + 6 sin(x) cos(x) in terms of cos(2x) and sin(2x)


Find the x and y coordinates of the turning points of the curve 'y = x^3 - 3x^2 +4'. Identify each turning point as either a maximum or a minimum.


Can you teach me how to rationalise the denominator of an algebraic expression?


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