How to use the quadratic formula, using the following equation: x^2 + 3x - 4

To begin you must identify the co-efficients of each x term, essentially what number comes before x2 , x and the integer value.

a = 1, b = 3, c = -4 . We then substitute these values into the quadratic formula:  x = ( -b +- SQRT (b2 - 4ac) ) ÷ 2a . For the top half of the formula we end up with:  - 3 +- SQRT (32 - 4 x 1 x (-4)). This simplifies to -3 +- 5 = 2 or -8.

On the bottom of the formula we simply get 2 x 1 = 2. Therefore our 2 answers for x are x = 2 ÷ 2 or x = -8 ÷ 2 which results in x being equal to x = 1 or -4.

OB
Answered by Oliver B. Maths tutor

2754 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

A farmer has a garden shaped into an isosceles triangle. Its side is 7m. He needs to enclose the perimeter, using copper wires, in order to avoid undesirable incidents. Each meter of copper wire cost 2£. How much does he need to pay to secure his garden?


How do you factorise x^2 +5x+6?


Solve the simultaneous equation: 2x + y = 18, x - y = 6


How would I expand 3 brackets, e.g. (x + 3)(x + 4)(x + 2)?


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