How do you multiply #4a ^ { 3} b ^ { - 2} \cdot 9a ^ { - 5} b#?

1 Answer
Sep 8, 2017

See a solution process below:

Explanation:

First, rewrite the expression as:

#(4 * 9)(a^3 * a^-5)(b^-2 * b) =>#

#36(a^3 * a^-5)(b^-2 * b)#

Next, use this rule of exponents to rewrite #b#:

#x = x^color(blue)(1)#

#36(a^3 * a^-5)(b^-2 * b^color(blue)(1))#

Then, use this rule of exponents to multiply the #a# and #b# terms:

#x^color(red)(a) xx x^color(blue)(b) = x^(color(red)(a) + color(blue)(b))#

#36(a^color(red)(3) * a^color(blue)(-5))(b^color(red)(-2) * b^color(blue)(1)) =>#

#36a^(color(red)(3)+color(blue)(-5))b^(color(red)(-2)+color(blue)(1)) =>#

#36a^-2b^-1#

Next, use this rule of exponents to eliminate the negative exponents:

#x^color(red)(a) = 1/x^color(red)(-a)#

#36a^color(red)(-2)b^color(red)(-1) =>#

#36/(a^color(red)(- -2)b^color(red)(- -1)) =>#

#36/(a^2b^1)#

Now, use this rule of exponents to complete the simplification:

#x^color(red)(1) = x#

#36/(a^2b^color(red)(1)) =>#

#36/(a^2b)#