WVGSA Grade 6 Expressions and Equations. Practice it free.

The constants $15$ and $-7$ are like terms: $15 - 7 = 8$. The term $r^{2}$ stays the same, so the expression is equivalent to $r^{2} + 8\textsf{.}$

Distribute 5: $5 \cdot 9x + 5 \cdot -5 = 45x - 25$.

$3^{4} = 3 \cdot 3 \cdot 3 \cdot 3 = 81\textsf{.}$

The base $6$ appears $3$ times as a factor, so $6 \times 6 \times 6 = 6^{3}$.

Multiply first: $7 \cdot 9 = 63$. Then $4 + 63 - 3 = 64$.

$\,3^2 = 3 \cdot 3 = 9$.

The constants $8$ and $2$ are like terms: $8 + 2 = 10$. The term $3z$ stays the same, so the expression is equivalent to $3z + 10\textsf{.}$

Combine $x$-terms: $1x + 2x = 3x$. Combine constants: $6 - 8 = -2$. Result: $3x - 2$.