a)5xy²-(8x³y⁴):(2x²y²)+x*3y²=
=5xy²-4xy²+3xy²=
=5xy²
b)9x³(-2xy²)-14xy²x³+(-5x²y²)*(-x²)=
=-18x⁴y²-14x⁴y²+5x⁴y²=9x⁴y²
c)a²x-3a(-2ax)+5x(-0,2a²)=
=a²x+6a²x-a²x=6a²x
d)-2/3x(-3x)²+5/9x⁶:(20/27x³)-0,6x(-5x²)=
=2x³+5/9x⁶ *(27/20x³)+3x³=
=2x³+3x³/4+3x³=
=5x³+3x³/4=
=23x³/4
e)6/5x(-x)²+1/4x⁵:(0,5x²)+(-1/2x)²(-x)=
=-6/5x³+1/2x³+1/2x³=
=-6/5x³+x³=- x³/5
f)3/4x(-9/8x)+(4x²)²:(-x)²-9*(-1/3x)²=
=-27/32x²+16x²+3x²=
=-27/32x²+19x²=
=-27+608/32x²=
=581/32x²