Answer:
45
Step-by-step explanation:
45 +45=90
The system of equations that can be used to determine the number of tetra fish and goldfish purchased is:
x = 2 y. 2 x + 1.5 y = 20
<h3>What are the system of equations ?</h3>
In order to determine the required values, two linear equations would be formed from the question. The two equations would exhibit the relationship between the two types of fishes:
The first equation would show the ratio between the two types of fishes bought: 2y = x
Th second equation would show the total cost of the two type of fish:1.5y + 2x = 20
To learn more about simultaneous equations, please check: brainly.com/question/16763389
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The given function is,
.
Or, 
To find the inverse of a function, first step is to switch x and y. Therefore,

Next stpe is to solve the above equation for y t get the inverse f f(x). Hence, multiply each sides by y + 5 to get rid of fraction form. So,

xy + 5x = 2y - 1
xy = 2y - 1 - 5x Subtract 5x from each sides to isolate y.
xy - 2y = -5x - 1 Subtract 2y from each sides.
y(x - 2) = -5x -1 Take out the common factor y.
Divide each sides by x-2.

So, 
Now when we will compare
with
then we will get a = -5, b = -1, c = 1 and d=-2
So, 
Hope this helps you!
One factor will be zero, hence y will be zero, when x=-3.
The other factor will be zero, hence y will be zero, when x=-5.
The zeros of the function are x ∈ {-5, -3}.
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This solution makes use of the "zero product rule," which states a product is zero if and only if one or more factors is zero.