15x^2 + x =2

Question

how to solve using quadratic equation

Answer 1

First, write this equation in standard form

ax^2 + bx + c = 0.

 

The quadratic formula is

 

x = {-b +/- sqrt[b^2 - 4ac]}/2a

 

where sqrt stands for square root.

 

So, we write your equation as

15x^2 + x - 2 = 0

a = 15, b = 1, and c = -2

 

x = {-1 +/- sqrt[1 - 4(15)(-2)]}/(2*15)

 

x = {-1 +/- sqrt[1 + 120]}/30

 

x = {-1 +/- sqrt[121]}/30 

 

x =  {-1 +/- 11}/30

 

x = (-1 + 11)/30 - 10/30 = 1/3

and

x = (-1-11)/30 - -12/30 = -2/5