Needed help with this math question.

Question

5x^2 + 8x -69 = 0

x = ?

Answer 1

My solution is very simple. you can change it as (x-3)(5x-23)=0, thus x=3 or x=23/5.

The first floor is very general way. Here, like this kind of equation,  you can use the simplest and fast method to solve it.

Answer 2

A classic quadratic equation (a fancy name for a second-degree polynomial) takes this form: ax^2 +bx + c

In this equation your coefficient, a = 5, b = 8, and c = -69

With this in mind, you could go in two familiar directions from this point. You could either:

1). divide the whole equation by 5, in order to get rid of the first coefficient and try to factor by grouping. There's one problem with this method in this case though, because 8/5 and -69/5 are NOT integers, and so it will be impossible for you to find two numbers that add to equal 8/5 and multiply to be 69/5. So don't try this method, as it proves useless.

2). Let's do things the old-fashioned way, using the Quadratic Formula! We already have our coefficients, a, b and c, and now all we have to do is plug them into the formula itself. Remember, that the Quadratic Forumla is used to find the roots of x in any second-degree polynomial, and is as follows:

 

x = -b ± sqrt(b^2 - 4ac)/2a

 

Take the positive and negative roots of the equation, and you will have your roots for x.

 

**sqrt = square root