The answer to this question is C
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)
First you need to know some rules 2 numbers that are the same with coefficients divided : you differentiate those coeff
and multyplied :you sum up them
12x^8/3x^3= 4x^8-3=4x^5
20^2x=20^x*20^x
m^5*m^-7=m^5-7=m^-2
its just the form of counting and not necessarily the different number
(a) The sum of length and width is half the perimeter, so the breadth in terms of length (x) in cm will be
.. breadth = 34 -x
(b) Then the expression for the area (in cm^2) is
.. area = length*breadth
.. 253 = (x)(34 -x)
.. x^2 -34x +253 = 0 . . . . . subtract the right side, eliminate parentheses
.. (x -11)(x -23) = 0 . . . . . . . factor
.. x = 11 or 23
The dimensions of the rectangle are 11 cm by 23 cm.
