Because this is a fourth degree that will be tricky to factor as it is, we will do a u substitution. Let $x^2=u$ . We can now rewrite that polynomial in terms of u: $u^2-7u-8=0$ . Filling into the quadratic formula we have $u=\frac{7+/-\sqrt{49-4(1)(-8)}}{2}$ . Simplifying down $u=\frac{7+/-\sqrt{81}}{2}$ and $u=\frac{7+9}{2}$ or $u=\frac{7-9}{2}$ . That means that u = 8 or u = -1. But don't forget that we let $u=x^2$ , so we have to put x-squared back in for u. That gives us $x^2=8$ which simplifies down to $+/-2\sqrt{2}$ . That also gives us $x^2=-1$ . When we take the square root of -1, we have to use the fact that -1 = i^2, so we sub that in to get $x=+/-i$ . All in all, your solutions are as follows: $2\sqrt{2},-2\sqrt{2},i,-i$ which is choice b.

7 0

2 years ago

Question 6 of 10 Multiple Choice: Please select the best answer and click "submit." What is the greatest number of acute angles

gavmur [86]

2. it can't have three because one of them is a right triangle do D doesn't add up. It can't have 0 because an obtuse angle plus a right angle would go over 180 degrees. So, the most it can have is 2 acute for example 90(right angle) 30(acute) and 60 (acute) is a possible answer. Also, a right angle can only have two acute angles since an obtuse angle would put it over 180 which was already stated

3 0

2 years ago

!!! CAN SOMEONE HELP !!! (PLEASE ILL GIVE BRAINLIST)

vladimir1956 [14]

Answer:

120 minutes

Step-by-step explanation:

the total bill was $58 so we have to subtract the $40 monthly bill part to find how much extra money she paid because her call was over 200 minutes

58-40=18

Then divide the $18 by $0.15 since the $18 is the total amount of each time she was charged $0.15 for going 1 minute over 200 minutes

18÷0.15 = 120

120 is te Amount Of minutes she went over her 200 minute limit

6 0

2 years ago

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