y=-2x
We know this because the slope is -2 (slope is found using rise/run, in this case the rise is 2 and the run is -1, so 2/-1=-2), and the y-intercept is at 0 (the y-intercept is the point at which a line crosses the y-axis).
:)
Answer: 
On a keyboard you would type sqrt(41)
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Work Shown:


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A slight alternative is to plot the point M(2,-5) to form right triangle LMN. The 90 degree angle is at point M.
The legs are of length LM = 4 and MN = 5, which are found by subtracting the x coordinates together and the y coordinates together (or you can count the spaces). From there, use the Pythagorean theorem to get the hypotenuse LN.
The distance formula is an altered version of the Pythagorean theorem.
Answer:
9
Step-by-step explanation:
it's an isosceles right ∆.
so (9√2)^2 = 81*2= 162 = 2s^2
let x=y=s
s^2 = 81
s = 9
5cm,7cm,and 10cm? im no professional but might wanna double check first
Answer:
Step-by-step explanation:
-10 and 9
-10×9=-90
-10+9=-1