need help solving a problem (show me your steps :))

R

ruskofat

New member
Joined
Aug 6, 2015
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3
here is is

7i * 3i(-8 - 6i)

i get -168iE2 - 126iE3
the answer book and google both show 168 + 126i

what did i do wrong?

7i * 3i = 21iE2
21iE2(-8 - 6i) = -168iE2 - 126iE3

^ my steps
 
ruskofat said:
here is is

7i * 3i(-8 - 6i)
Click to expand...
It's odd that your grammar-school arithmetic class is covering complex numbers.... :shock:

I will guess that the instructions were something like "simplify the expression".

ruskofat said:
i get -168iE2 - 126iE3
Click to expand...
How? What were your steps? What is the meaning of "E2" and "E3"? How did they come into play? For instance, what would have been your answer if you'd been asked to multiply 7 and 3?

Please be specific. Thank you! ;)
 
Well, from what I gather, the E2 and E3 are simply non-standard ways of writing "squared" and "cubed" respectively. With that assumption in mind, your work is fine and the only thing you did "wrong" was not simplifying. The answer you come up with is -168i2 - 126i3. But now you have to ask yourself, what is the value of i2? And what is the value of i3? Keep in mind that i is not a variable in this problem.
 
ksdhart said:
Well, from what I gather, the E2 and E3 are simply non-standard ways of writing "squared" and "cubed" respectively.
Click to expand...
If the expressions are generated by software, then they're standardly an indication of scientific-type notation, as in "3.6 x 10^12" being formatted as "3.6E12".
 
stapel said:
If the expressions are generated by software, then they're standardly an indication of scientific-type notation, as in "3.6 x 10^12" being formatted as "3.6E12".
Click to expand...

Yeah im used to coding syntax and we use e for scientific notation, thank for the help i forgot what i was for a sec :/
but I remembered what i is and it all made sense lol
 
stapel said:
It's odd that your grammar-school arithmetic class is covering complex numbers.... :shock:

I will guess that the instructions were something like "simplify the expression".


How? What were your steps? What is the meaning of "E2" and "E3"? How did they come into play? For instance, what would have been your answer if you'd been asked to multiply 7 and 3?

Please be specific. Thank you! ;)
Click to expand...

Sorry a typo made you so upset - and i didnt know they didnt teach computers in forum dickhead school
 
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