Simple quadratic solutions?

Question

-10= -1/2 (9.8)t2 + (2.0)t.....the formula given is -b +- the square root of b2-4ac /(over) 2a

Answer 1

You have to first set it up to be in this form:

at² + bt + c = 0, so:

-10 = (-1/2)(9.8)t² + 2t

(1/2)(9.8)t² - 2t - 10 = 0

4.9t² - 2t - 10 = 0

t = [ -b ± √(b² - 4ac)] / 2a

t = [ -(-2) ± √((-2)² - 4(4.9)(-10))] / 2(4.9)

t = [ 2 ± √(4 +196)] / 9.8

t = [ 2 ± √(200)] / 9.8

t = [ 2 ± 10√(2)] / 9.8

Roudning to 2 decimal places:

t = -1.24 and 1.65

Answer 2

-10= -1/2 (9.8)t2 + (2.0)t Simplify and put in standard form

4.9t^2 -2t -10 = 0

x1 = 1.64716

x2 = -1.23899