Question

(14y+21)(1,8-0,3y)=0

Answer 1

14у+21=0
14у=-21
у=-21/14
у=-1,5

1,8-0,3у=0
0,3у=1,8
у=1,8/0,3
у=6

Answer 2

25,2у+4,2у^2+37,8-6,3у=0
-4,2у^2+18,9у+37,8=0
у^2-4,5-9=0
D=b^2-4ac=(-4.5)^2-4*1*(-9)=20.25+36=56.25  √=7,5
х1,2=(-b±√D)/2=(4,5±7,5)/2
x1=6
x2=-1.5