<span>(3х+у)(2х-5у)-6(х-у)^2 =
= 6x^2 - 15xy + 2xy - 5y^2 - 6x^2 + 12xy - 6y^2 =
= -xy - 11y^2</span>
Решение в фотке:
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<span>d^2+0,2d+0,01−36d^2=0
35d</span>²-0,2d-0,01=0
D=0,04+1,4=1,44
d1=(0,2-1,2)/70=-1/70
d2=(0,2+1,2)/70=1,4/70=14/700=1/50