anonymous
  • anonymous
write the expression as a complex number in standard form. (10-4i)(3+4i)
Mathematics
  • Stacey Warren - Expert brainly.com
Hey! We 've verified this expert answer for you, click below to unlock the details :)
SOLVED
At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.
jamiebookeater
  • jamiebookeater
I got my questions answered at brainly.com in under 10 minutes. Go to brainly.com now for free help!
mathstudent55
  • mathstudent55
Use FOIL to multiply together like we did yesterday: (10 - 4i)(3 + 4i) = 10 * 3 + 10 * 4i - 4i * 3 - 4i * 4i Now do all 4 multiplications
anonymous
  • anonymous
10*3=30 10*4i=40i 4i*3=12i 4i*4i=16i
mathstudent55
  • mathstudent55
Almost. Look at the last one: 10*3=30 10*4i=40i 4i*3=12i 4i*4i=16i^2 = 16 * (-1) = -16

Looking for something else?

Not the answer you are looking for? Search for more explanations.

More answers

anonymous
  • anonymous
so -16 how do we put it all together
mathstudent55
  • mathstudent55
10 * 3 + 10 * 4i - 4i * 3 - 4i * 4i = 30 + 40i - 12i - (-16)
mathstudent55
  • mathstudent55
10 * 3 + 10 * 4i - 4i * 3 - 4i * 4i = 30 + 40i - 12i - (-16) = 30 + 28i + 16 = 46 + 28i
anonymous
  • anonymous
5/1+2i
mathstudent55
  • mathstudent55
You mean this, right? |dw:1370971515053:dw|
anonymous
  • anonymous
yeah
mathstudent55
  • mathstudent55
You need to multiply the numerator and denominator by the complex conjugate of the denominator.
mathstudent55
  • mathstudent55
Can you write the complex conjugate of the denominator?
anonymous
  • anonymous
1-2i
mathstudent55
  • mathstudent55
Right. Now we need to multiply.
mathstudent55
  • mathstudent55
|dw:1370972032537:dw|
anonymous
  • anonymous
the 1-2i cancels out
mathstudent55
  • mathstudent55
No. The whole idea of multiplying is to get rid of the i in the denominator.
mathstudent55
  • mathstudent55
|dw:1370972426124:dw|
anonymous
  • anonymous
7+2i/4i
mathstudent55
  • mathstudent55
What is the complex conjugate of 4i? Multiply the numerator and denominator by it.

Looking for something else?

Not the answer you are looking for? Search for more explanations.