# How do you expand 5(2y+3)?

$10 y + 15$
To expand this you need to multiply each term inside the parenthesis by the term outside the parenthesis, in case $5$:
$5 \left(2 y + 3\right) \implies \left(5 \cdot 2 y\right) + \left(5 \cdot 3\right) \implies 10 y + 15$