I need sum major help!!!!!?

Question

Can you do this for me? ... Solve each equation by using the quadratic formula. Round to the nearest tenth if necessary.....................
1.) -2x^2+18=7x...................... x^2+4x= -20

Answer 1

1. -2x^2-7x+18
a= - 2, b=-7. c=18
substitute them into
x= -b+-sqrt(b^2-4ac)/2a

2. x^2+4x+20=0
a=1 b=4 c=20

Answer 2

rearranging
-2x^2-7x+18=0
a=-2
b=-7
c=18

in standard form
ax^2+bx+c=0
you can now use the quadratic formula
x=-b+ or - squareroot((b^2-(4*a*c))/2*a)
ahh something liek that but uh..
has 2 real roots
1) -5.2231109973624505
2)1.723110997362451

solveed via http://www.math.com/students/calculators/source/quadratic.htm
I warn you in advance..DO YOUR OWN HOMEWORK. ASK YOUR PROFESSOR OR TEACHER. GET A STUDY BUDDYS PHONE NUMBER AND OR EMAIL...get them on instant messenger.

2)
bring the -20 to other side and flip the sign
there is x so there is invisible 1 in front of it
1x^2+4x+20=0
lets see the discriminant (which tells you about how many roots)

b^2-(4*a*c)
b=4
4^2-(4*1*20)
16-(4*20)<0
THEREFORE, NO REAL ROOTS,
if you must solve using imaginary then um...ahhhhhh
i forget lol..
but the derivative is um lol ...get to Calculus..
2x+4
maybe this is useful
but put it somehow in the form of
a+bi

oh ya I remember somewhat now..you solve using long divison and then using imaginary somehow..
where -1 = i^2
and then ...
you can get rid of the negative under the divison sign.

Answer 3

-2x^2+18=7x

2x² + 7x - 18=0

x = (-b +- √(b² - 4ac))/2a

x = (-7 +- √(49 + 144))/4

x = (-7 +- √(193))/4

x² + 4x = -20

x² + 4x + 20= 0

x = (-b +- √(b² - 4ac))/2a

x = (-4 +- √(16 - 80))/2

x = (-2 +- 4i)
.

Answer 4

-2x^2 + 18 = 7x
2x^2 + 7x -18 = 0
x = (-7 +/- sqrt(49 + 144))/4
x = (-7 +/- sqrt(193))/4
x = (-7 +/- 13.9)/4
x = 6.9/4 or -20.9/4
x = 1.7 or -5.2

x^2 + 4x + 20 = 0
x = (-4 +/- sqrt(16-80))/2
x = (-4 +/- sqrt(-64))/2
x = -2 +/- 4i

Answer 5

-2x^2 - 7x + 18 = ...

Really, you are going to have to learn the formula yourself, you knwo.

It is a simple ditty. Which I keep forgetting, but ...

-a +/- (b^2 -4ac)^1/2 / 2a ??? nah ....

so I google ....

-b etc ...
so:
{-(-7) +/- [7^2 - 4.(-2).18] }/2.(-2) etc.

Further I go not here ....

Lazybones that I am. (*wink*)