Question 343301
The ladder is the hypotenuse of a right triangle with a base x and altitude x+3.
x^2+(x+3)^2=15^2
x^2+x^2+6x+9=225
2x^2+6x-116=0
x^2+3x-58=0
x=6.262...' see below
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Ed
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 *[invoke quadratic "x", 1, 3, -58]