Adding and Subtracting Radical Expressions

Question

anonymous · Answer

$$3\sqrt{2x}+x \sqrt{8x}-5\sqrt{18x}$$

anonymous · Answer

If someone simplified  $$-10x \sqrt{2x}$$ what did he do wrong?

unklerhaukus · Answer

can you facotrise  8 ,  and 18 so that one of the factors is a square number ?

anonymous · Answer

You could simplify 8 to be $$2\sqrt{2}$$ and 18 could be simplified to $$3\sqrt{2}$$

unklerhaukus · Answer

yeah thats right

anonymous · Answer

My question is that it asks me that if someone got $$-10x \sqrt{2x}$$ what did he do wrong when simplifying?

unklerhaukus · Answer

so can you tell me the correct simplification?

anonymous · Answer

$$3\sqrt{2x}+2x \sqrt{2x}-3\sqrt{2x}$$

anonymous · Answer

The first and last would cancel each other out so you would be left with the one in the middle.

unklerhaukus · Answer

dont forget, the last term had a co-efficient of 5

$$3\sqrt{2x}+x \sqrt{8x}-5\sqrt{18x}$$
$$=3\sqrt{2x}+2x \sqrt{2x}-5\times3\sqrt{2x}$$

anonymous · Answer

oh yea :P

anonymous · Answer

$$3\sqrt{2x}+2x \sqrt{2x}-15\sqrt{2x}$$
$$-12\sqrt{2x}+2x \sqrt{2x}$$

unklerhaukus · Answer

Thats it,

now if you compair with 'someone's answer, maybe they forgot a factor

anonymous · Answer

Could it be that they added the 2 as well even though its not a like term?

unklerhaukus · Answer

yeah, i think they may have forgot this x , and hence added the terms 
$$-12\sqrt{2x}+2\color{gray}x \sqrt{2x}$$

anonymous · Answer

oh I see thank you :)