what is 15 = -y + 10

It's a simple linear equation in a single variable, 'y' .  Its solution is the number that 'y' must be in order to make the equation a true statement.  Here's how to find the solution:Write the equation:    15 = -y + 10Subtract 10 from each side:    5 = -yMultiply each side by -1 :      -5 = y

15=-y+10=-10+15=-y=5=-y=-5=ywelcome :)