How do you solve x^2 + x - 12 = 0x2+x12=0?

2 Answers
Mar 9, 2016

The solutions are:

x =3x=3

x = -4x=4

Explanation:

x^2 + x-12 =0x2+x12=0

The equation is of the form color(blue)(ax^2+bx+c=0ax2+bx+c=0 where:

a=1, b=1, c=-12a=1,b=1,c=12

The Discriminant is given by:

Delta=b^2-4*a*c

= (1)^2-(4*1*(-12))

= 1 +48 =49

The solutions are found using the formula
x=(-b+-sqrtDelta)/(2*a)

x = ((-1)+-sqrt(49))/(2*1) = (-1+-7)/2

x = (-1+7)/2 = 6/2 =3

x = (-1-7)/2 = -8/2 = -4

The solutions are:

x =3

x = -4

Mar 9, 2016

x=-4,3

Explanation:

x^2+x-12=0

This is in the form of a Quadratic equation
(in form ax^2+bx+c=0)

Where

a=1,b=1,c=-12

Use Quadratic formula

x=(-b+-sqrt(b^2-4ac))/(2a)

Substitute the values

rarrx=(-1+-sqrt(1^2-4(1)(-12)))/(2(1))

rarrx=(-1+-sqrt(1-(-48)))/(2)

rarrx=(-1+-sqrt(1+48))/(2)

rarrx=(-1+-sqrt49)/(2)

rarrx=(-1+-7)/2

Now we have two values for 2

x=(-1-7)/2,x=(-1+7)/2

If we solve for it,We get

rArrx=-4,3