I dont know how solve this problem:
Solve 4y+1=2y+8
our objective here, is to get y on one side of the equal sign by itself. whatever we don't want on one side, we subtract it from both sides of the equation. so let's do that.
$\displaystyle 4y + 1 = 2y + 8$
Let's get the y's on the left side. so i want to get rid of the 2y on the right, so subtract it from both sides.
$\displaystyle \Rightarrow 4y + 1 - 2y = 2y - 2y + 8$
$\displaystyle \Rightarrow 2y + 1 = 8$
Now let's get rid of the 1 on the left side
$\displaystyle \Rightarrow 2y + 1 - 1 = 8 - 1$
$\displaystyle \Rightarrow 2y = 7$
Now divide both sides by 2
$\displaystyle \Rightarrow \frac {2y}{2} = \frac {7}{2}$
$\displaystyle \Rightarrow y = \frac {7}{2}$
remember, the objective was to get y only on one side. at the end i had 2y, i needed to have only y. when i divided by 2, it canceled the 2 that was beside the y, so i was left with y on one side, like i wanted. but since it is an equation, whatever i do on one side, i have to do on the other to keep things equal. so i divided by 2 on the right side as well to get 7/2