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Plz help solve for x question is in pic

Plz help solve for x question is in pic-example-1
User Avi
by
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1 Answer

7 votes

Answer:

(x, y) = (5, -3)

Explanation:

Apparently, you're asked to solve for x first. This suggests you will be substituting for x in the quadratic. This works, but may make the problem more difficult than it has to be.

Using the found value of x, we have ...

y = (2 -y)^2 -11(2 -y) +27

y = 4 -4y +y^2 -22 +11y +27 . . . . eliminate parentheses

y^2 +6y +9 = 0 . . . . . . . . . . . . . put in standard form

(y +3)^2 = 0 . . . . . . . . . . . . . . factor

y = -3 . . . . . . . . . . . . . . . . . the value of y that makes the factor zero

x = 2 -(-3) = 5

The one solution is (x, y) = (5, -3).

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Alternate solution

The two expressions for y can be equated:

x^2 -11x +27 = -x +2

x^2 -10x +25 = 0 . . . . . rearrange to standard form

(x -5)^2 = 0 . . . . . . . . factor

x = 5 . . . . . . . . . . . x that makes the factors zero

y = -5 +2 = -3 . . . corresponding value of y

This solution removes the need for the "eliminate parentheses" step in the original solution, so cuts down on the opportunity for error.

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The attached graph shows the one solution is the point where the line is tangent to the parabola.

Plz help solve for x question is in pic-example-1
User Paul Weiland
by
4.4k points