also, neither of the zeros should be included with the brackets
i chose a test point of 1 and plugged it in and its negative so why isnt that included in the interval? i also chose a test point of ten and plgged it in and the answer was positive so why is that in the interval?
I didn't multiply it by -x, I multiplied it by x. When you multiply by a negative number, you have to flip the inequality, so it's easier to just multiply by a positive number.
You can't go from 45 - 4x - x^2 to x^2 - 4x - 45 without changing something because the x^2 is negative and the 45 is positive. If you wanted to change the signs, you would have to multiply both sides by -1, which turns 45 - 4x - x^2 < 0 to -45 + 4x + x^2 > 0. That factors to (x + 9)(x - 5).
Jay im so confused and frustrated that im crying i just cant get this problem ive been trying for days and everyone i ask is giving me different answers that dont match with the professors answer
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if you factor the quadratic, you get (x+5)(X-9), not the other way around
i chose a test point of 1 and plugged it in and its negative so why isnt that included in the interval?
i also chose a test point of ten and plgged it in and the answer was positive so why is that in the interval?
45/10 - 4 - 10 = 4.5 - 4 - 10 = -9.5 < 0 so it checks.
45/1 - 4 - 1 = 45 - 4 - 1 = 41 > 0 so it's not.
i even checked it
i got the zeros that the answer gave me...
im getting -10 and a valid test point!
-9: 45/-9 - 4 + 9 = -5 - 4 + 9 = 0
-5: 45/-5 - 4 + 5 = -9 - 4 + 5 = -8 =/= 0
5: 45/5 - 4 - 5 = 9 - 4 - 5 = 0
9: 45/9 - 4 - 9 = 5 - 4 - 9 = -8 =/= 0
i just cant get this problem
ive been trying for days and everyone i ask is giving me different answers that dont match with the professors answer