A river flows at 2m/s. Juan’s boat can travel twice as fast down the river as it can go up the river. How fast can the boat go i
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Answer:
30
Step-by-step explanation:
This problem can be done without the Distance Formula (which is a way to find the distance between any two points in the plane).
The attached image shows the points and segments joining them.
PQ = 5 because the points are on the same horizontal line, and you can count spaces between them (or subtract x-coordinates: 4 - (-1) = 5).
PR = 12 because the points are on the same vertical line; count spaces or subtract y-coordinates, 7 - (-5) = 12.
The triangle is a right triangle, so the Pythagorean Theorem can be used to find the length of the hypotenuse.
The perimeter of the triangle is 5 + 12 + 13 = 30
The fact that the coefficients are pairwise identical (except for sign) tells you that x^2 -1 is a factor (and x-5 is the other factor). Of course, you recognize x^2-1 as a special form (the difference of squares) that is factored as (x +1)(x -1).
The zeros are x = -1, +1, +5.
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A graphing calculator confirms this.
The zeros are x = -1, +1, +5.
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A graphing calculator confirms this.