Quadratic equations are mathematical equations where the unknown x is expressed as the power of 2 (i.e. x2). To solve these equations, we need to arrange the equation in the form:
ax2+ bx+ c = 0
And it has 2 answers (in some cases, only one of them has a physical answer), the answer is given by:
For example, we are solving the equation:
x2 – 2x – 15 = 0
We have a = 1
b = -2
c = -15
Using the equation given before:
We have the following 2 answers:
To ensure that these are the right answers, we can replace x in the equation
x1:
52 – 2*(5) – 15 = 0
25 – 10 – 15 = 0
0 = 0
x2:
(-3)2 – 2*(-3) – 15 = 0
9 + 6 – 15 = 0
0 = 0