write the LCD for each given rational expression and convert to equivalent rational w/ LCD denominators?

Question

3/4b^2-9 , 2b/2b+3 , -5/2b^2-3b
Any help Please

Answer 1

You need to use parentheses when you transpose questions to yahoo answers single line format. The expressions should look like this:
3/(4b^2 - 9), 2b/(2b + 3), -5/(2b^2 -3b)

Factor the denominators:
3/((2b + 3)(2b - 3)), 2b/(2b + 3), -5/(b(2b - 3))
LCD = b(2b + 3)(2b - 3)
First has to be multiplied by b/b, second by b(2b - 3)/(b(2b - 3)),
third by (2b + 3)/(2b + 3)
3b/LCD, 2b^2(2b - 3)/LCD, -5(2b + 3)/LCD

Answer 2

Lowest undemanding denominator = least undemanding diverse of the denominators for this reason, we've 12 and 20 12 = 2^2 *3 20= 2^2 *5 factors 2,3,5. So carry jointly the words, 2^2*3*5 = 60 So, sixty is the backside undemanding denominator. 5/12 = 5*5/12*5 = 25/60 3/20 = 3*3 / 20*3 = 9/60 sturdy luck!