Answer:
See Explanation
Step-by-step explanation:
(a) Proof: Product of two rational numbers
Using direct proofs.
Let the two rational numbers be A and B.
Such that:


The product:




Proved, because 1/3 is rational
(b) Proof: Quotient of a rational number and a non-zero rational number
Using direct proofs.
Let the two rational numbers be A and B.
Such that:


The quotient:

Express as product



Proved, because 3/4 is rational
(c) x + y is rational (missing from the question)
Using direct proofs.
Let x and y be
Such that:


The sum:

Take LCM


Proved, because 7/6 is rational
<em>The above proof works for all values of A, B, x and y; as long as they are rational values</em>
Her situation can be modeled by the linear equation (in standard form):
x*$0.25 + y*$0.79 = $2.50
<h3>How to write the equation that represents her situation?</h3>
The variables that we will use here are:
x = number of apples that she can buy.
y = number of bananas that she can buy.
We know that she has $2.50 to spend, that each apple costs $0.25 and each banana costs $0.79, then the cost of the x apples and y bananas is:
x*$0.25 + y*$0.79
and that must be equal to the amount she has to spend, then we can write the linear equation:
x*$0.25 + y*$0.79 = $2.50
That is the linear equation in standard form that represents her situation.
Learn more about linear equations:
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Answer:
20
Step-by-step explanation:
Convert 80% into a decimal and multiply by 25
Convert 80% into a decimal form: 0.8
Multiply 0.8 by 25 = 0.8 x 25
Simplify 0.8 x 25
=20
Sorry if this answer is incorrect!
The Area is the width<span> times the </span>height<span>: A = w x h;
Then, 64 = w x h;
h = 4 + w;
64 = 4w + w^2;
w^2 + 4w - 64 = 0;
We solve this equation: w1 </span>≈ 6,24 > 0 (okay); w2 ≈ - 10,24 < 0 (not okay);
<span>Finally, h1 </span>≈ 10,24;<span>
</span>