Quadratic formula?.... what's the answer to 5x^2-3x+1? and 2x^2-15X-8?

Answer 1

The quadratic formula is:
-b +/- √(b^2 - 4ac)
-------------------------------- = x
2a

1.) 5x^2-3x+1
-(-3) +/- √((-3)^2 - 4(5)(1))
---------------------------------------------- = x
2(5)

= (3 +/- √(9 - 20)) / 10
= .3 +/- .33166i (solution!)

check:
(x + .3 + .33166i)(x + .3 - .33166i)
(x + .3 + .33166i)(x + .3 - .33166i) = x^2 + .3x - .33166ix + .3x + .09 - .99498i + .33166ix + .99498i - .0.1099983556i^2 (i^2 = -1)
Combine like terms:
x^2 + .6x + .0.1999983556
Multiply the whole thing by 5:
5x^2 + 3x + 1 (check!)

2.) 2x^2 - 15x - 8
-(-15) +/- √((-15)^2 - 4(2)(-8))
---------------------------------------------- = x
2(2)

= (15 +/- √(225 + 64)) / 4
= 15/4 +/- 17/4
= -1/2 and 8 (solution!)

check:
(x - 1/2) (x + 8) = x^2 + 8x - 1/2x - 4 = x^2 - 7 1/2x - 4
Multiply by 2: 2x^2 - 15x - 8) (check!)

Answer 2

to 5? i circulate to assume this is a '+' a million) x^2 +3x +5 +x^2 +4x+a million 2x^2 +7x +6 2) 6x(x^3 +5x^2 +3x +a million) 6x^4 +30x^3 +18x^2 +6x 3) 4(2x^2+3x^2y +5xy^2 +3y^2) 8x^2 +3x^2y +20xy^2 +12y^2

Answer 3

-.032, .632

-.5, 10.5