# Pre-Cal

posted by .

Perform the operation and write the result in standard form.

(2-3i)(5i) over 2+3i

Please help!! I do not understand this.

• Pre-Cal -

(2-3i)(5i) over 2+3i
= 5i(2-3i)/(2+3i)
multiply top and bottom by 2-3i

= 5i(4 - 12i + 9i^2)/(4-9i^2)
= 5i(-13 - 12i)/13
= (-65i - 60i^2)/13
= (60 - 65i)/13

or 60/13 - 5i if by standard form you mean a + bi

• oops arithmetic error Pre-Cal -

ok, Kim ,I messed up in the arithmetic

but, if you understand what I did, you should be able to fix it yourself.

hint: the error is from
= 5i(4 - 12i + 9i^2)/(4-9i^2) to
= 5i(-13 - 12i)/13

• Pre-Cal -

YOU SHOULD KNOW HOW TO DO THIS!

## Respond to this Question

 First Name School Subject Your Answer

## Similar Questions

1. ### Advanced Algebra

I some problems that I need help with please. Add or subtact as indicated and write the results in standard form. 4. 6-(-5+7i)-(7-2i) Divide and express the result in standard form. --These problems I don't understand, do you have …
2. ### Precalculus

Perform the indicated operation and the write the result in standard form (6+ sq root -5)(6 + sq root -7)=
3. ### Pre-Cal

Perform the addition or subtraction and write the result in standard form. (8+sqrt -18) - (4+3sqrt2i) I know that you have to subtract 8 from 4 but I do not know what to do after this.
4. ### math

Perform the operation and write the result in standard form. 8 + 20i over 2i Please explain, I am very confused!!
5. ### math

Perform the operation and write the result in standard form. 1 + i over i - 3 over 4 - i Do I have to multiply top and bottom by i?
6. ### pre calc - polynomials & factoring

perform the opertaion and write the result in standard form... (2x^2 + 1) - (x^2 - 2x + 1)
7. ### math

Perform the indicated operation(s) and express the result in standard form. Leave answers in terms of square roots (do not use decimals). (-9-sqrt-3)^2
8. ### college algebra

Perform the indicated operation(s) and express the result in standard form. Leave answers in terms of square roots (do not use decimals). (-9-sqrt-3)^2
9. ### math

Perform the operation and write the result in standard form. 9i - (5 + 3i)
10. ### Pre-calc

Perform the operation and write the result in standard form. ___16___ 2x+2

More Similar Questions