21÷xy=? With x=-3 y=2
1 answer:
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<h3>Answer:</h3>
D (0, 5), (5, 0)
<h3>Step-by-step explanation:</h3>Anything with -5 and 0 will not satisfy x+y=5. This eliminates the first three choices.
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It is easiest to check the offered answers. You can also solve this graphically, or by solving the simultaneous equations.
You can, for example, square the first equation and subtract the second:
... (x+y)² -(x²+y²) = 5² -25
... 2xy = 0
This will be true for x=0 or for y=0, so (0, 5) and (5, 0) are solutions to the pair of equations.