(10х+19)(6х+7)-3(4х-8)(5х+13)=1
60x²+114x+70x+133 - 3(20x²-40x+52x-104)=1
60x²+114x+70x+133 - 60x²+120x-156x+312=1
148x +445=1
148x=-444
x=-3
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9z²-(3z-5)²=20
9z²-((3z)²-2·3z·5+25)=20
9z²-9z²+30z-25=20
30z=45
z=1,5
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(13х-2)²-(12х-5)²-(-5х-4)²=160
(169x²-52x+4)-(144x²-120x+25)-(25x²+40x+16)=160
169x²-52x+4-144x²+120x-25-25x²-40x-16=160
28x=197
x=197/28
x=7целых 1/28