Question

what is the simplified form of 9y^5/15x^7 times 5x^3/45y^2
help!!!

Answer 1

the options are a) 15x^3/y^4
b) 15x^4/y^3
c) y^4/15x^3
d) y^3/15x^4

Answer 2

do you remember this?
\[ \frac{a}{b}\frac{c}{d}=\frac{ac}{bd} \]
and
\[\large \frac{a^n}{a^m}=a^{n-m}=\frac{1}{a^{m-n}} \]

Answer 3

not really..... can you explain it to me?

Answer 4

OK! you have
\[ \large \frac{9y^5}{15x^7}\cdot\frac{5x^3}{45y^2} \]
when you multiply fractions you do it numerator times numerator and denominator times denominator so you get what?

Answer 5

i thought you cant do that cause they arent like terms?

Answer 6

yes you dont mix unlike terms but since you have multiplication, u just put them together

Answer 7

so you have
\[ \large \frac{(9y^5)(5x^3)}{(15x^7)(45y^2)} \]

Answer 8

now \[ 9\times5=45 \]
so you can cancel out 9 and 5 in the numerator with 45 in the denominator, right?

Answer 9

ya

Answer 10

wouldnt you cancel out the 45 too?

Answer 11

so you now have
\[ \large \frac{y^5x^3}{15x^7y^2} \]
can you apply the rules i gave at the beginning?

Answer 12

so the answer is y^3/ 15x^4 ?

Answer 13

aka D

Answer 14

Yes!

Answer 15

yaaay thank you