Question

Which of the following is equal to the sqrt 9*4

a) 18
b) sqrt 9/4
c) 36
d) srt9*sqrt4

Answer 1

`√(a)=b\iff b^2=a\ for\ a\geq0\ \wedge\ b\geq0\\---------------------\\\\Method\ \#1:\\\\√(9\cdot4)=√(36)=6\ because\ 6^2=36\\\\d)\ \sqrt9\cdot\sqrt4=3\cdot2=6\\\\\sqrt9=3\ because\ 3^2=9;\ \sqrt4=2\ because\ 2^2=4\\\\Answer:\ \boxed{d)\ \sqrt9\cdot\sqrt4}\\\\Method\ \#2:\\\\\text{use}\ √(a\cdot b)=√(a)\cdot√(b)\\\\√(9\cdot4)=\sqrt9\cdot\sqrt4\\\\\text{Therefore your answer is}\ \boxed{d)}`