Properties of Equality Addition Property of Equality Subtraction Property of Equality For real numbers a, b, and c, if a = b, For real numbers o, b, and c, if a = b, then a +C= then a-c= Multiplication Property of Equality Division Property of Equality For real numbers a, b, andc, if a = b and For real numbers o, b, and c, ifo =b and cz0, C0, then a c then = C

[tex]\begin{gathered} \frac{2}{3}y\text{ + 15 = 9} \\ \text{Subtract both sides }by\text{ 15} \\ \frac{2}{3}y\text{ + 15 -15 = 9 - 15} \\ \text{This is a subtraction property of equality} \\ \frac{2}{3}y\text{ = -}6 \end{gathered}[/tex][tex]\begin{gathered} \text{Multiply both sides by the inverse of }the\text{ coefficient of y} \\ \text{coefficent of y = 2/3 } \\ inverse\text{ of the }coefficent\text{ of y = 2/3} \\ \frac{2}{3}y\times\frac{3}{2}\text{ = -6}\times\text{ }\frac{3}{2} \\ it\text{ is a Multiplication property of equality: }a\times c\text{ = b}\times\text{ c} \\ y\text{ = -18/2} \\ \end{gathered}[/tex][tex]y\text{ = -9 }[/tex]