Anyone please help me. I’m learning about Solving Systems of Equations using substitution

Question 1 is
{Y=3x-2
{Y-3x=4

And question 2 is
{0.8x-0.2y=1.5
{0.1x+1.2y=0.5

I don’t really understand it please help

So the point is to use what y equals to combine the x’s and the numbers.

So y= 3x-2
In y-3x=4
(3x-2)-3x=4
3x-2-3x=4
0-2=4
Hmm either the question is wrong or the set does not exist.

Q2
0.8x-0.2y=1.5
0.1x+1.2y=0.5

I’ll choose to isolate x from the second equation.

0.1x+1.2y=0.5
0.1x=0.5-1.2y
x=(0.5-1.2y)/0.1
.5/.1 -1.2/.1
x=5-12y

Using this sub into first equation
0.8(5-12y)-0.2y=1.5
Distribute
4-9.6y-0.2y=15
Combine like terms
-9.8y=11
11/-9.8
y= -1.12