What is 3x - y = 17 x + y = -5

Mathematics

1 answer:

Virty [35]3 years ago

3 0

Answer:

{x,y}={6,1}

Step-by-step explanation:

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PLEASE HELP ME!!!!!!!!!

vitfil [10]

$(x - 4) {}^{2} - 28 = 8 \\ (x - 4) {}^{2} = 8 + 28 \\ (x - 4) {}^{2} = 36$

This must be true for some value of x, since we have a quantity squared yielding a positive number, and since the equation is of second degree,there must exist 2 real roots.

$\sqrt{(x - 4) {}^{2} } = ± \sqrt{36} \\x - 4 = ±6 \\ x _{1}- 4 = 6 \: \: \: \: \: \: \: \: \: \: x _{2}- 4 = - 6 \\ x_{1} = 6 + 4 \: \: \: \: \: \: \: \: \: \: x_{2} = - 6 + 4 \\ x_{1} = 10 \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: x_{2} = - 2$

Well he started off correct to the point of completing the square.

$(x - 3) {}^{2} = 16 \\ x - 3 = ±4 \\ \: x_{1} - 3 = 4 \: \: \: \: \: \: \: \: \: \: \: \: x_{2} - 3 = - 4 \\ x_{1} = 7 \: \: \: \: \: \: \: \: \: \: x_{2} = - 1$