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Mathematics 15 Online
makkyy:

What is the remainder when (2x^4−4x^2−16) is divided by (x+2)

snowflake0531:

Okay, have you learned either long division for polynomials or synthetic division yet?

makkyy:

prolly but i dont really pay attention

snowflake0531:

Ok So, which one do you want to use, long division or synthetic division (synthetic division is shorter, easier after youget how to do it

makkyy:

synthetic ig

snowflake0531:

Okay so we have to set it up For synthetic division, we divide it be (x-_), which means that because int his we are dividing by x+2, we have to use -2

snowflake0531:

Also, we only write down the coefficients for these

snowflake0531:

And because we don't have x^3 or x, we fill it in as a 0

makkyy:

ok

snowflake0531:

|dw:1616170681117:dw| it looks confusing, but each of the numbers are actually just coefficients

makkyy:

ok

snowflake0531:

And so, we drop down each one, multiply it by -2, but it to above the line, etc., i'll show you|dw:1616170791174:dw|

snowflake0531:

|dw:1616170804079:dw| multiply 2 and -2

snowflake0531:

|dw:1616170833673:dw| different than long division, synthetic division does addition

snowflake0531:

|dw:1616170881777:dw| multiply -2 and -4

snowflake0531:

|dw:1616170902148:dw| add -4 and 8

snowflake0531:

|dw:1616170931730:dw| multiply -2 and 4

snowflake0531:

|dw:1616170954199:dw| add 0 with -8

snowflake0531:

|dw:1616170978401:dw| mutliply

snowflake0531:

And so, we are left with 0 at the end if at the end you do not get 0 for once, that means that that is the remainder

snowflake0531:

So, filling in the gaps again with those x's you get 2x^3 + -4x^2 +4x-8

makkyy:

do i just solve it from there?

snowflake0531:

._. that's your answer

makkyy:

oh im stupid i swear lol

snowflake0531:

What we just did was divide you didn't get any of it? oof

makkyy:

the answers im given on the question are -16, -8, 0, and 8

snowflake0531:

\(\color{#0cbb34}{\text{Originally Posted by}}\) @snowflake0531 And so, we are left with 0 at the end if at the end you do not get 0 for once, that means that that is the remainder \(\color{#0cbb34}{\text{End of Quote}}\)

snowflake0531:

Which means that it is 0

makkyy:

ohh

snowflake0531:

The division was perfect, there's no remainder

makkyy:

oka i get it

snowflake0531:

yw~

makkyy:

thanks!

snowflake0531:

yw~, it was fun

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