First you substitute in the 8 for x. you then multiply 8 times 8 which equals 64. you subtract 64 from 4 and 64, since it would be the opposite of addition. you would then take the -10y=-60, and you would divide by negative 10 to get y by itself. since negative 60 divided by negative 10 is a positive 6, your answer would be y equals 6.
