Question

What are the approximate solutions of 2x^2 + 9x = 8 to the nearest hundredth?

Answer 1

2x^2 + 9x - 8 = 0
you can use the quadratic formula to solve this

x = [ -b +- sqrt(b^2 - 4ac)] / 2a

Answer 2

here a, b and c are the values in the general equation
ax^2 + bx + c = 0

Answer 3

need any ore help?

Answer 4

*more

Answer 5

yea

Answer 6

ok -

2x^2 + 9x - 8 = 0 - compare this with ax^2 + bx + c = 0

so a = 2, b = 9 and c = -8
plug these into the formula:

x =[ -9 + sqrt(9^2 - 4 * 2 * -8)] / 2*2
= [ -9 + sqrt(81+64)] / 4
= -9/2 + sqrt 145

also other root is -9/2 - sqrt 145

these work out to 7.54 or -16.54 to nearest one hundredth

Answer 7

then what?

Answer 8

no more those are the solutions: (7.54,-16.54)

Answer 9

the answers are suppose to be one of these.


x ≈ 1.22 and x ≈ 3.28
x ≈ -0.76 and x ≈ 5.26
x ≈ -1.22 and x ≈ -3.28
x ≈ -5.26 and x ≈ 0.76

Answer 10

oh - ok - i know my method is ok - i might have made a mistake in the calculations
i'll re-check

Answer 11

brb

Answer 12

yeah - i see my mistake
its on last line
it should be
-9/4 + sqrt145/4
= -2.25 + 3.01 = 0.76
and -2.25 - 3.01 = -5.26

answer 0.76 and -5.26