You said that (xy) = 16, and (x+y) = 4 .
From the second equation you can get [ x = 4 - y ],
then substitude that for 'x' in the first equation, and
finally, rearrange the first equation to read
<u>x² - 4x + 16 = 0</u>
Don't even try to factor that quadratic equation. Go straight
to the quadratic formula, and the two solutions you find are ...
<em>x = 2 + i 2√3</em>
and
<em>x = 2 - i 2√3</em> .
Those are the two number that do what you want.
There are no <u>real</u> numbers that can do it.
Answer:
- A (-4, -3)
- C (2, 4)
- E (3, 2)
Step-by-step explanation:
It is convenient to use technology to plot the points and the functions to see what lies where. The first attachment shows such a plot.
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Of course, you can do the function evaluations. For example, testing answer B, we find ...
... 3·6 ≤ -2·1 +18 . . . . <em>false</em> for the first equation — not a solution
Checking all the points requires 10 function evaluations. When things get repetitive like that, I like to use a graphing calculator or spreadsheet.
_____
<em>Using a calculator</em>
The second attachment shows a calculator evaluating the viability of each point as a solution. The equations have been rearranged to ...
- -2x -3y +18 ≥ 0
- -x +4y +12 ≥ 0
This makes it easy to look at the evaluation results to see if the solution is viable or not.
The x-values of the points are entered into list L₁ and the y-values into L₂. The result of the first inequality above is in L₃ and the result for the second inequality is in L₄. Any negative value in L₃ or L₄ shows a point that is <u>not</u> part of the solution set. Points B and D fail to match problem requirements.
Points A, C, and E are in the solution set.
Answer:
9.67 x 10^4
Step-by-step explanation:
5.8 x 10^6 / 60
= 96700 minutes
= 9.67 x 10^4 minutes
5x^3+8x^2/3x^4-16x^2=x^2(5x+8)/x^2(3x^2-16)=5x+8/3x^2-16
lim x--->0 5x+8/3x^2-16=8/-16=-1/2