Simplify 5i*(5+3i)

$5 i \cdot (5 + 3 i)$

Apply the distributive property.

$5 i \cdot 5 + 5 i (3 i)$

Multiply $5$ by $5$ .

$25 i + 5 i (3 i)$

Multiply $5 i (3 i)$ .

Multiply $3$ by $5$ .

$25 i + 15 i i$

Raise $i$ to the power of $1$ .

$25 i + 15 (i^{1} i)$

Raise $i$ to the power of $1$ .

$25 i + 15 (i^{1} i^{1})$

Use the power rule $a^{m} a^{n} = a^{m + n}$ to combine exponents.

$25 i + 15 i^{1 + 1}$

Add $1$ and $1$ .

$25 i + 15 i^{2}$

Simplify each term.

Rewrite $i^{2}$ as $- 1$ .

$25 i + 15 \cdot - 1$

Multiply $15$ by $- 1$ .

$25 i - 15$

Reorder $25 i$ and $- 15$ .

$- 15 + 25 i$