75.7k views
16 votes
PLEASE HELP how do i solve (5-3i)^2

User OMG Ponies
by
3.6k points

2 Answers

7 votes

Answer:

16−30i

Explanation:

Use Square of Difference: {(a-b)}^{2}={a}^{2}-2ab+{b}^{2}(a−b)

2

=a

2

−2ab+b

2

.

{5}^{2}-2\times 5\times 3\imath +{(3\imath )}^{2}

5

2

−2×5×3+(3)

2

2 Simplify {5}^{2}5

2

to 2525.

25-2\times 5\times 3\imath +{(3\imath )}^{2}

25−2×5×3+(3)

2

3 Use Multiplication Distributive Property: {(xy)}^{a}={x}^{a}{y}^{a}(xy)

a

=x

a

y

a

.

25-2\times 5\times 3\imath +{3}^{2}{\imath }^{2}

25−2×5×3+3

2

2

4 Simplify {3}^{2}3

2

to 99.

25-2\times 5\times 3\imath +9{\imath }^{2}

25−2×5×3+9

2

5 Use Square Rule: {i}^{2}=-1i

2

=−1.

25-2\times 5\times 3\imath +9\times -1

25−2×5×3+9×−1

6 Simplify 2\times 5\times 3\imath2×5×3 to 30\imath30.

25-30\imath +9\times -1

25−30+9×−1

7 Simplify 9\times -19×−1 to -9−9.

25-30\imath -9

25−30−9

8 Collect like terms.

(25-9)-30\imath

(25−9)−30

9 Simplify.

16-30\imath

16−30

User Orenshi
by
3.5k points
3 votes

Answer:

16-30i

Explanation:

This is what I got :)

User Gwaredd
by
3.6k points