Question

I need helpwith these 3 questions please!

1. radical 10 (11+ radical 5)
2. 7 over 10i
3. radical 49 over (3+4i)-(2-5i)

Please help!

Answer 1

What are the questions here? I'm not sure I understand. Do you need to simplify? Rationalize?

Answer 2

yes simplify. im sorry

Answer 3

1. 10√(1/5) - √45 - 12√(5/9)
10√(1/5) - √9√5 -(12/3)√5
10√(1/5) - 3√5 - 4√5
10√(1/5) - 7√5

2. You have to know that each numbers has factors

10 has the factors 10 and 1 and 5 and 2

12 has factors 12 and 1, 6 and 2 and 4 and 3

You simplify by doing the same to numerator (top number) and denomiator (bottom number).

The only common factors are 1 and 2. Since 1 leaves you with the same expression you take the higher number 2 to get 5/6.

If you knew multiplication tables you would see the answer inherently. I am not sure those tables are taught in schools anymore. They are here:

http://www.mathsisfun.com/timestable.htm …

3.i dont know

Answer 4

\[\frac{7}{10i}=\frac{7}{10i}\times \frac{i}{i}=\frac{7i}{-10}=-\frac{7i}{10}\]

Answer 5

#3, first of
\[\sqrt{49}=7\] and
\[(3+4i)-(2-5i)=1-i\]so start with
\[\frac{7}{1-i}\]

Answer 6

then
\[\frac{7}{1-i}=\frac{7}{1-i}\times \frac{1+i}{1+i}=\frac{7(1+i)}{2}\]

Answer 7

last line because
\[(a+bi)(a-bi)=a^2+b^2\]

Answer 8

then standard form looks like
\[\frac{7}{2}+\frac{7}{2}i\]

Answer 9

the answers to the first question is
A.-11 radical 10 + 5 radical 2
B. -5 radical 2 + 11i radical 10
C. 5 radical 2 - 11i radical 10
D. 11 radical 10 + 5 radical 2

Answer 10

yeah, they were all wrong..

Answer 11

thanks for your effort though