Multiplying Rational Expressions

[crappiefisher26]

How did they get this?

. . .(2x^3 / 5y^2) * (10y / 3x^2)

. . .= (2x^3 * 10y) / (5y^2 * 3x^2)

. . .= 4x / 3y

 

[Denis]

how did they get this.
(2x^3/5y^2)*(10y/3x^2)=(2x^3*10y)/5y^2*3x^2)=4x/3y

"they got this" by simple multiplication, then simplification :!:

EXAMPLE of simplification: x^5 / x^3 = x^(5-3) = x^2

 

[crappiefisher26]

Multiplying ration Expressions

Thanks Dennis. Heres the questions im stuck on

3a/2*4/a^2

how did they get 4x/3y from (2x^3*10y)/(5y^2*3x^2)

im not quite sure i understand that yet.

 

[stapel]

Re: Multiplying ration Expressions

how did they get 4x/3y from (2x^3*10y)/(5y^2*3x^2)

"They" did just what the tutor said: They multiplied the fractions and then simplified.

Are you not familiar with multiplying fractions? Because you can't very well work with rational expressions unless you're very solid on regular (numerical) fractions. If you don't understand how "they" go from, say, (3/5)(20/21) to (1/1)(4/7) = 4/7, then you need to back up a bit before trying to work with rational expressions.

Eliz.