How exactly, do you apply the quadratic formula on an equation?

Question

I know the formula: x= -b +/- square root (b^2- 4ac), divided by 2a.

So, let's say the equation is 15x^2+7x-55

How would you do it?
What is your answer if the problem tells you to "Solve using the quadratic formula?"

Thanks!

Answer 1

It's as simple as plugging in numbers. The number 15 becomes the letter "a", the number 7 is "b", and the number 55 is "c". Just substitute the number for the letter in the formula and solve.

Answer 2

You just take the coefficients of your equation and plug them into the formula. For instance, 15x²+7x-55=0 means that x=((-7)±√(7²-4(15)(-55)))/(2(15)). Simplifying, x=(-7±√(49+3300))/30, x=(-7±√3349)/30. If you want a numerical solution, plug that into your calculator to get x≈2.1623515061640381895499601389022 or x≈-1.6956848394973715228832934722355.

Answer 3

The quadratic formula is in the form ax^2 +bx + c with a,b,c being the constants in front of the x. Thus in your equation. a=15, b=7, c=-55

Just plug in and solve.

Answer 4

You know the quadratic equation. You also know your formula. Simply plug in the a, b,c from the equation into the quadratic equation and solve the quadratic equation to find the solution to your original equation. This said, using the fornula is faster than trying to explain how to use it.

Answer 5

generalized quadratic formula comes from a quadratic eqn i.e
Ax2 +bx+c=o
using this model in your quadratic formula
a will represents the coefficient of X squared
b which is the sum the coefficient of X
c is the constant
if u identify these key areas the rest will be evaluation or filling in the blanks
hope this is helpful

Answer 6

a, b, and c are the coefficients of each term in the quadratic equation.

a=15
b=7
c=-55

therefore you simply insert these 3 numbers into the formula...

[-7 +/- sqrt(7^2-4*15*-55)]/(2*15) = (-7 +/- 57.87)/(2*15)

x = 1.696 & -2.16

You get two answers because it is a second order equation.

Answer 7

The quadratic formula only applies to an equation. You dont have an equation, you only have an expression, and there is no formula for that.

If on the other hand you set your expression equal to something, then you can use your handy dandy formula.

Answer 8

in case you permit t=x^2 then the equation turns into 4t^2-65t+sixteen=0. making use of the quadratic formulation one gets t=(sixty 5+-sqrt(4225-256))/8 =(sixty 5+-sqrt(3969))/8 =(sixty 5+-sixty 3)/8 giving us 2 ideas for t, 128/8=sixteen and a pair of/8=a million/4. Recalling that t equals x^2 we get right here ideas for x: 4, -4, a million/2, -a million/2.

Answer 9

i dont know but in pythagoriam therom, A squared= B squared=C squared.

So a is 3 and b is four. C is...


5!!!!

Answer 10

15x^2 + 7x - 55

x = (-b ± sqrt(b^2 - 4ac))/2a

a = 15
b = 7
c = -55

x = (-7 ± sqrt(7^2 - 4(15)(-55)))/(2(15))
x = (-7 ± sqrt(49 + 3300))/30
x = (-7 ± sqrt(3349))/30
x = (1/30)(-7 ± sqrt(3349))