Answer:
y=4
Step-by-step explanation:
in a 45-45-90 triangle sides a and b are equal and the hypotenuse is 
so in this case y is a leg, so it is 4
in case there is a part two where they ask what x is, it would be 
The coefficient of (3y² + 9)5 is <u>15</u>.
A polynomial is of the form a₀xⁿ + a₁xⁿ⁻¹ + a₂xⁿ⁻² + ... + aₙ₋₁x + aₙ.
Here, x is the variable, aₙ is the constant term, and a₀, a₁, a₂, ..., and aₙ₋₁, are the coefficients.
a₀ is the leading coefficient.
In the question, we are asked to identify the coefficient of (3y² + 9)5.
First, we expand the given expression:
(3y² + 9)5
= 15y² + 45.
Comparing this to the standard form of a polynomial, a₀xⁿ + a₁xⁿ⁻¹ + a₂xⁿ⁻² + ... + aₙ₋₁x + aₙ, we can say that y is the variable, 15 is the coefficient, and 45 is the constant term.
Thus, the coefficient of (3y² + 9)5 is <u>15</u>.
Learn more about the coefficients of a polynomial at
brainly.com/question/9071229
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