Goal: solve for y. First step: Multiply out 5(y+2) and also 4(2y-1):
5y + 10 and 8y - 4
Then your original 5(y+2) = 13+ 4(2y-1)
becomes 5y + 10 = 13 + 8y - 4
Combining the y terms: 10 = 13 + 3y - 4
Simplifying the right side: 10 = 3y + 9
Subtracting 9 from both sides: 1 = 3y. Solving for y: y = 1/3