#\frac { 12x + 12} { 3- \frac { 3} { x^ { 2} } }#
First we will calculate the denominator separately:
#{ 3- \frac { 3} { x^ { 2} } }#
#=> 3(x^2/x^2)- \frac { 3} { x^ { 2} } #
#=> (3x^2 - 3)/ x^2 #
Now we know #a-: b/c = axx c/b#
#therefore \frac { 12x + 12} { 3- \frac { 3} { x^ { 2} } }# can be written as:
# =>(12x + 12) xx ( frac { x^2} { 3x^ { 2} -3 } )#
# =>(cancel12^4(x + 1) xx x^2 ) /{ cancel3^1(x^ { 2} -1) } #
#=> (x^2(x+1))/ (x^2-1)#
Now substitute #(x^2-1) = (x+1)(x-1)#;
#=> (x^2(x+1))/( (x-1)(x+1))#
#=> (x^2cancel((x+1)))/( (x-1)cancel((x+1)))#
#=> x^2/ (x+1)#