Question #85711

1 Answer
Jan 18, 2017

#r=(23*5)/(x+7)=115/(x+7) => r^2=115^2/(x+7)^2=13225/(x^2+14x+49)#
#=(23^2*5^2)/(x+7)^2#

Explanation:

#r=(23*5)/(x+7) => r^2=((23*5)/(x+7))^2=(23*5)^2/(x+7)^2=((23)^2(5)^2)/((x+7)(x+7))#

#=((20+3)^2(25))/(x*x+7x+7x+7(7))#

#=(((20)(20)+(3)(20)+(3)(20)+(3)(3))(25))/(x^2+14x+49)#

#=((400+60+60+9)(25))/(x^2+14x+49)#

#=((400+120+9)(25))/(x^2+14x+49)=((529)(25))/(x^2+14x+49)#

#=((529)(20+5))/(x^2+14x+49)=(529(20)+529(5))/(x^2+14x+49)#

#=(2(5290)+5290(1/2))/(x^2+14x+49)=(10580+2645)/(x^2+14x+49)#

#13225/(x^2+14x+49)#