Assuming these are supposed to be:
2x(x-10)=20; (1) x+8=-4-3x=24, 4x+2=14 or (2) x+8=-4, -3x=24, 4x+2=14
2x(x-10)=20 becomes x(x-10)=10 after dividing through by 2.
x²-10x=10, x²-10x+25=10+25, (x-5)²=35, x-5=±√35, x=5±√35.
(1) x+8=-4-3x=24 implies x+8=-4-3x, 4x=-12, x=-3; buy x+8=24, so x=16 which is inconsistent with x=-3, and also -4-3x=24, -28=3x, implying x=-28/3, inconsistent with other solutions; or
(2) x=-12, x=-8, 4x=12 making x=3. There appear to be three separate equations.
The question(s) is(are) unclear.