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If 1 / X-1 / y = 3, what is the value of 5x + 2xy-5y / x-4xy-y Write process online = urgent!
1/x-1/y=3
(y-x)/xy=3
y-x=3xy
x-y=-3xy
(5x+2xy-5y)/(x-4xy-y )
=[5(x-y)+2xy]/[(x-y)-4xy]
=[5*(-3xy)+2xy]/(-3xy-4xy)
=-13xy/(-7xy)
=13/7
If 1 / X-1 / y = 3, find 5x + 2xy-5y / x-4xy-y
Because 1 / X-1 / y = 3
Multiply both sides by XY to get Y-X = 3xy, X-Y = - 3xy
So the original formula = [5 (X-Y) + 2XY] / (x-y-4xy)
=(-5*3xy+2xy)/(-3xy-4xy)
=(-13xy)/(-7xy)
=13/7
As shown in the figure, in equilateral △ ABC, point D is the midpoint of BC side, and ad is taken as the edge to make equilateral △ ade. (1) find the degree of ∠ CAE; (2) take the midpoint F of AB side, connect CF and CE, and try to prove that quadrilateral afce is rectangular
(1) ∵△ ABC is an equilateral triangle, and D is the midpoint of BC, which is bisected by ∵ Da, that is, ∵△ DAE is an equilateral triangle, and ∵ △ DAE is an equilateral triangle, with ∵ DAE = 60 °, and ∵ CAE = ∵ Dae - ∵ CAD = 30 °; (2) it is proved that ∵ △ BAC is an equilateral triangle, f is the midpoint of AB, CF ⊥ AB, BFC = 90
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