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# Most efficient way to use your calculator for solving a quadratic equation? watch

1. Howdy ,

I can't find anything that shows how to use my calculator to solve a quadratic equation.

What is the most efficient way to input it into a calculator (Casio fx-83GT PLUS)
to solve an equation?

e.g.

Thanks
2. Just use the quadratic formula. All of the buttons for it are on the calculator.

By the way - it's where you have the equation: Attachment 516091516093

So in your case:

a = 3
b = 7
c = -13

You should get 2 results of x (since you use a plus and a minus next to the -b), and you literally just plug in the numbers into the formula. You don't need to learn the equation off by heart, but I did, since it is worth doing.
Attached Images

3. Get a graphic calculator.

Put y=f(x) and y=0 in the graph menu.
Graph it.
Find the point of intersection of the two lines.
4. (Original post by marcus888)
Howdy ,

I can't find anything that shows how to use my calculator to solve a quadratic equation.

What is the most efficient way to input it into a calculator (Casio fx-83GT PLUS)
to solve an equation?

e.g.

Thanks
yea i'm sure this one can't solve quadratics, like the person above suggested >.> you need a newer version of this calculator

(Original post by ishaggedyourmum)
You have to use the FX991ES plus calculator, this cr*ppy one cant solve quadratics.

btw, i shagged your mum
looks like you shag more mums than their partners do
5. on my caso fx-9750GII it's just on option 8 for equation, it solves them up to 6 degrees!
6. You don't need a calculator to solve quadratic equations. However if you do feel the need to use one just put the following into the calculator and press equals:

[-b +/- sqrt(b^2 -4ac)]/2a

where: Ax^2 + Bx + C = 0

Though I advice you look into methods such as factorising and completing the square in order to solve quadratic equations, both are quick and easy and don't require you to spend £££ on a calculator that has a graphing function just to find out that your maths exam is a non calculator one, or that the calculator that you picked up which draws graphs is actually banned in the exam.
7. Both factorising and completing the square can be pretty difficult at GCSE if a (the co-efficient of x) is greater than 1.
8. When using the ac method to factorise, I find the prime factorising function on my calculator to work out what numbers multiply to give ac that add up to b.

That quadratic requires the quadratic formula or completing the square where you express in the form .
9. (Original post by Fractite)
Both factorising and completing the square can be pretty difficult at GCSE if a (the co-efficient of x) is greater than 1.
Ok but considering that this is on the specification for most major exam boards for the non calculator GCSE maths examination, it is something that is a requirement. I am also pretty sure that factorising and completing the square are a lot easier than using the quadratic equation without a calculator.

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