Question

PLEASE AND THANK YOU CONFUSED ON THIS

Answer 1

After staring at this for a few seconds, I think the equation

$-5\sqrt{10}\cdot\sqrt{15}=[1]\sqrt{[2]}$

is asking you to simplify the left hand side so that it has a form matching the right hand side, and [1] and [2] are placeholders. My guess is that they're supposed to be integers.

Notice that

$\sqrt{10}=\sqrt{5\cdot2}=\sqrt5\cdot\sqrt2$

$\sqrt{15}=\sqrt{5\cdot3}=\sqrt5\cdot\sqrt3$

$\implies\sqrt{10}\cdot\sqrt{15}=(\sqrt5)^2\cdot\sqrt2\cdot\sqrt3=5\sqrt{2\cdot3}=5\sqrt6$

Then multiplying by -5, we have

$-5\sqrt{10}\cdot\sqrt{15}=-25\sqrt6$

so I believe [1] = -25, and [2] = 6.