You can put this solution on YOUR website! Compute the distance between the two points (1-√2,-1) and (2+√2, 4).
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d^2 = diffy^2 + diffx^2
d^2 = 5^2 + (1 + 2sqrt(2))^2
= 25 + 1 + 4sqrt(2) + 8
d^2 = 34 + sqrt(32)
d^2 =~ 39.65685
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d =~ 6.29737