Distribute 2/5 to (y+10)=
2/5y+4=0
After Transpose (leave the numbers only in the rights side, then numbers with letters on the left side)
2/5y=0-4
You might wonder why is the 4 negative. Always remember any number that passes through the = sign becomes opposite.
2/5y=(-4)
Multiply the both sides by 5
(5)2/5y=(-4)(5)
Cancel 5 and drop y
2y=(-20)
Divide it both by 2
2y/2=(-20)/2
Cancel 2 and drop y. Leave the negative sign.(on the right)
y=-10
And that's the FINAL ANSWER