To find the answer to "What two numbers have a product of 91 and a sum of 30?" we first state what we know. We are looking for x and y and we know that x • y = 91 and x + y = 30.
Before we keep going, it is important to know that x • y is the same as y • x and x + y is the same as y + x. The two variables are interchangeable. Which means that when we create one equation to solve the problem, we will have two answers.
To solve the problem, we take x + y = 30 and solve it for y to get y = 30 - x. Then, we replace y in x • y = 91 with 30 - x to get this:
x • (30 - x) = 91
Like we said above, the x and y are interchangeable, therefore the x in the equation above could also be y. The bottom line is that when we solved the equation we got two answers which are the two numbers that have a product of 91 and a sum of 30. The numbers are:
3.42416
26.57584
That's it! The two numbers that have a product of 91 and a sum of 30 are 3.42416 and 26.57584 as proven below:
3.42416 • 26.57584 ≈ 91
3.42416 + 26.57584 = 30
Note: Answers are rounded up to the nearest five decimals if necessary so the answers may not be exact.
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