NeeD AnSwErS!!! FaSt!!!! AlGeBrA 2?

Question

Solve:

x^2-4x=0
3x^2-21x+36=0
x^2+1=-8

SOLVE BY COMPLETING THE SQUARE:

x^2-4x+3=0
x^2-6x+25=0

thanks I got the first part, all I need is the completeing the square now.

(there is another way to do it...:
set 2xy=(the bx)
so:
x^2-4x+3:
2xy=-4x
y=-2
put y^2 in place of c
x^2-4x+4
now its factorable??

Answer 1

x^2-4=0 becomes x^2 = 4 so you get (x+2)(x-2) = 0 and x = +2 and -2.

3x^2 - 21x +36 =0 becomes x^2 - 7x +12 = 0
If you look at the factors of 12 that add up to 7 you find 4 and 3
so (x-4)(x-3) = 0 so x = 4 and x = 3

x^2 + 1 = -8 becomes x^2 -9 = 0 so (x-3)(x+3) = 0 so x= +3 and -3

I hate completing the square method so I will leave that to someone else.

Answer 2

1) x^2 - 4x = 0

Factor x.

x(x - 4) = 0

Equate each factor to 0.

x = 0, x - 4 = 0
x = 0, x = 4

2) x^2 - 4x + 3 = 0

To complete the square, add and subtract half-squared of the coefficient of x.

x^2 - 4x + 4 + 3 - 4 = 0

Factor the now square trinomial.

(x - 2)^2 - 1 = 0

Move the -1 to the right hand side.

(x - 2)^2 = 1

Take the square root of both sides.

x - 2 = +/- 1

Move the 2 to the right hand side.

x = 2 +/- 1

Therefore, your answers are

x = { 2 + 1, 2 - 1 }

or, quite simply,

x = {3, 1}

Answer 3

circulate the variables of u to a minimal of one area of the equation: (-3/5u) - (2/3u) = (4/3) + (2) Take the least ordinary denominator for 5u and 3u it is 15u and for 3 and a million (2/a million) it is 3: (-9/15u) - (10/15u) = (4/3) + (6/3) (-19/15u) = (10/3) bypass Multiply: -fifty seven = 150u u = -0.38

Answer 4

whoa!!! i'm in 6 grade and i thought r math was hard? I dont get algebra!!! when do you start learing it and is it hard?