Answer:
a. 
b. x = 4 (see steps below)
Step-by-step explanation:
Since the two polygons are similar, the sides are proportional to each other. Using a proportion, you can solve for 'x' using cross-multiplication and division:

Cross-multiply: 15(x + 3) = 21(x + 1)
Distribute: 15x + 45 = 21x + 21
Subtract '15x' from both sides: 15x + 45 - 15x = 21x + 21 - 15x or 45 = 6x + 21
Subtract '21' from both sides: 45 - 21 = 6x + 21 - 21 or 24 = 6x
Divide by 6 on both sides: 24/6 = 6x/6
Solve for x: x = 4
Answer:
(x+1)(3x+2) is the answer
Answer:
The boat traveling at 24 kph when John goes downstream.
Step-by-step explanation:
We are given the following in the question:
John has a boat that will travel at the rate of 15 kph in still water.
Let x be the speed of the current.
Speed of boat in upstream

Speed of water in downstream

Relation:

We have to find the speed of boat in downstream.
Time to travel upstream for 35 km = Time to travel 140 km downstream

Thus, speed of current is 9 kph.
Speed of boat in downstream = 15 + 9 = 24 kph.
Thus, the boat traveling at 24 kph when John goes downstream.
We have the <span> Trigonometric Identities : </span>secx = 1/cosx; (sinx)^2 + (cosx)^2 = 1;
Then, 1 / (1-secx) = 1 / ( 1 - 1/cosx) = 1 / [(cosx - 1)/cosx] = cosx /
(cosx - 1 ) ;
Similar, 1 / (1+secx) = cosx / (1 + cosx) ;
cosx / (cosx - 1) + cosx / (1 + cosx) = [cosx(1 + cosx) + cosx (cosx - 1)] / [ (cosx - 1)(cox + 1)] =[cosx( 1 + cosx + cosx - 1 )] / [ (cosx - 1)(cox + 1)] = 2(cosx)^2 / [(cosx)^2 - (sinx)^2] = <span> 2(cosx)^2 / (-1) = - 2(cosx)^2;
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