Surely not everyone gets easily solve quadratic equations, but actually it is not so difficult! In this instruction I, as a student who have completed 9th grade, I want to share the experience.
Instruction
Difficulty level: Easy
What you will need:
paper
pen/pencil and so on =)
brains
step 1
First, what is the quadratic equation? Square equation is called the equation of the form ax^2+bx+c=0, where x is a variable, a, b, and with some numbers, and not equal to zero.
2 step
To solve the quadratic equation we need to know the formula to its roots, i. e, for a start, the formula for the discriminant of a quadratic equation. It looks as follows: D=b^2-4ac. You can bring it yourself, but this is not usually necessary, just remember the formula (!) it will be very necessary in the future. As is the formula for the quarter discriminant more about it later.
3 step
Take as an example the equation 3x^2-24x+21=0. I will solve it in two ways.
step 4
Method 1. The discriminant.
3x^2-24x+21=0
a=3, b=-24, c=21
D=b^2-4ac
D=576-4*63=576-252=324=18^2
D>0, then the equation has 2 roots
x1,2= (-b - sqrt D)/2a (this is the formula of square root equations, remember her?)
x1=(-(-24) 18)/6=42/6=7
x2=(-(-24)-18)/6=6/6=1
5 step
Now is the time to remember the formula for a quarter of a discriminant that is capable of great facilitate the solution of our equation =) so, here's how it looks: D1=k^2-ac (k=1/2b)
Method 2. A Quarter Of A Discriminant.
3x^2-24x+21=0
a=3, b=-24, c=21
k=-12
D1=k^2 ac
D1=144-63=81=9^2
D1>0, then the equation has 2 roots
x1,2= k +/ square root of D1)/a
x1= (-(-12) +9)/3=21/3=7
x2= (-(-12) -9)/3=3/3=1
Appreciated how much easier solution?;)
Thank you for your attention and wish You every success in school =)
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