I'm very bad at math and i need with this question .

what is the value of y in the equation 6 + y = −3?

a.) −9
b.) −3
c.) 3
d.) 9

Y = -3. Yeah this can be hard at first but you'll get the hang of it, its simple once u have that clicking moment. 
What the goal is is to get y by itself, right? Then u would have y = blank and thats what u need because ur trying to find y. So to get y alone and have that y = blank, u can "balance the equation." That means if u add something on the left side of the equation (before the equal sign) u have to add it to the right. Same with subtraction. In this equation, u would subtract 6 from both sides so there would be no 6 left on the left and a 6 on the right instead. ask me questions if u need more help! :)