1/3x+1/5=3 4x+1/4x+3/4=0

Question

1/3x+1/5=3
4x+1/4x+3/4=0

Answer 1

№1
1/3*x+1/5=3
1/3*x=3-1/5
1/3*x=14/5
x=14/5*3
x=42/5=8.4
№2
4*x+1/4*x+3/4=0
(4+1/4)*x=-3/4
17/4*x=-3/4
x=-3/4*4/17
x=-3/17