For the answer to the question above,
<span>Let's work with the left-hand side
We're going to times cosx/1-sinx by 1+sinx/1+sinx, you can do this because 1+sinx/1+sinx is equal to 1, so you aren't really changing anything.
After you've times the top and bottom by 1+sinx, you get:
cosx(1+sinx) / (1-sinx)(1+sinx)
The denominator is a difference of squares, so you get 1-sin^2 x
what you have now is
cosx(1+sinx) / 1-sin^2x
You know that 1-sin^2x is equal to cos^2x
so know you have
cosx(1+sinx) / cos^2x
get rid of the cosx on top by simplifying and the cos^2x so that you're left with
(1+sinx) / cos x
Therefore cosx / 1- sinx = 1 + sinx / cos x</span>
a is given to us so just plug a into the first equation:
b-3 - 3b =9
Add 3 to both sides:
b-3b=12
Combine like terms:
-2b=12
Divide by -2 to get b by itself:
b=-6
The only answer with b as -6 is the first one, (-9,-6)
The students rented 4 small cars and 8 large cars.
Step-by-step explanation:
Given,
Number of people in small car = 4
Number of people in large car = 7
Total people in both type of cars = 72
Let,
x represent the number of small cars rented.
y represent the number of large cars rented.
According to given statement;
4x+7y=72 Eqn 1
y = 2x Eqn 2
Putting value of y from Eqn 2 in Eqn 1

Dividing both sides by 18

Putting x=4 in Eqn 2

The students rented 4 small cars and 8 large cars.
Keywords: linear equation, substitution method
Learn more about linear equations at:
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18- 4/9 = 17 9/9 - 4/9 = 17 5/9 litters