0.4 is four tenths. 0.4 = 4/10=2/5
-33,600. To get this you multiply -4,200 by 8
Answer:
or 
Step-by-step explanation:
Given

Required
Solve for x using:

First, we need to identify a, b and c
The general form of a quadratic equation is:

So, by comparison with 

Substitute these values of a, b and c in




Split the expression to two
or 
To solve further in decimal form, we have
or 
or 
or 
When you see an equation with parenthesis around it, you can use this:
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction
Otherwise known as PEMDAS.
We can see that in the equation, there are parenthesis, so we can open those. We open parenthesis by taking the number right next to the parenthesis (or outside the parenthesis) and we multiply that number by everything inside. So this is what it would look like:
-2x^2 - 10x + 8
See how the signs changed? This rule only applies when you multiply something, but here is how I think of it:
+ and + always equals +.
- and - always equals +.
- and + always equals -.
+ and - always equals -.
So that's it! Just to be clear, the answer is:
-2x^2 - 10x + 8
Hope I helped, sorry if I'm wrong!
`Mschmindy