Решите уравнение: а) 3(5х-4)-8х=4х+9 б) 19х-8(х-3)=66-3х в)0,2(0,7х-5)+0,02=1,4(х-1,6) г) 2,7(0,1х+3,2)+0,6(1,3-х)=16,02

а) $3(5x-4)-8x=4x+9$
$15x-12-8x=4x+9$
$7x-12=4x+9$
$3x=21$
$\boxed{x=7}$.

б) $19x-8(x-3)=66-3x$
$19x-8x+24=66-3x$
$11x+24=66-3x$
$14x=42$
$\boxed{x=3}$.

в) $0{,}2(0{,}7x-5)+0{,}02=1{,}4(x-1{,}6)$
$0{,}14x-1+0{,}02=1{,}4x-2{,}24$
$0{,}14x-0{,}98=1{,}4x-2{,}24$
$-0{,}98=1{,}26x-2{,}24$
$1{,}26=1{,}26x$
$\boxed{x=1}$.

г) $2{,}7(0{,}1x+3{,}2)+0{,}6(1{,}3-x)=16{,}02$
$0{,}27x+8{,}64+0{,}78-0{,}6x=16{,}02$
$-0{,}33x+9{,}42=16{,}02$
$-0{,}33x=6{,}60$
$\boxed{x=-20}$.