Answer:
Step-by-step explanation:
Let he speed of the boat on the lake is x.
<u>Considering the speed of the current it will take him:</u>
- 22.5/(x + 6) + 22.5/(x - 6) = 9
- 2.5 / (x + 6) + 2.5 / (x - 6) = 1
- 2.5(x - 6 + x + 6) = (x + 6)(x - 6)
- 2.5*2x = x² - 36
- x² - 5x - 36 = 0
- x = (5 ± √(5² + 4*36))/2 = (5 ± 13) / 2
- x = (5 + 13)/2 = 9 mph (negative root is discarded as the speed should be positive)
So first you would need to FOIL the problem (first-outer-inner-last) so you would multiply x by x and get {x²} then you would multiply x by 1 so you would get just plain {x} then multiply 2 by x so to get {2x} then multiply the last terms 2 and 1 together to get {2} so then put it all together = x² + x + 2x + 2 then you add like terms together so you end up with = x² + 3x + 2 as the answer
Answer:
see below
Step-by-step explanation:
1. 7x+2x+19x
(7, 2, 19) x
=28x
2. -6x-3+3x-9
-3x-3-9
=3x-12
3. (3x-4y) -(x+2y)
3x-4y-x-2y
=2x-6y
4. 18x5 - 6x3
90-18
=72
5. (x+5)(x-7)
x²-7x+5x-35
=x²-2x-35
Answer:
C aka the third one
Step-by-step explanation:
