What is -4 square root of 90 + 2 square root of 160?

Question

1888 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2018-04-30T17:20:28

#-4sqrt(10)#

#-4sqrt(90)+ 2sqrt(160) = ?#

Assuming this to be the question(unfortunately, the lack of math symbols makes it ambiguous), the answer shall be:

#= -4(3)sqrt(10) + 2(4)sqrt(10)#
^What I've done here is #sqrt(ab) = sqrt(a)sqrt(b)# (9 times 10 and 16 times 10 respectively)

# = -12sqrt(10)+ 8sqrt(10)#
# = -4sqrt(10) #

Answer 2 · 2018-04-30T17:26:19

# -4 \sqrt{90} + 2 \sqrt{160}# #= -12 sqrt{10} + 8 sqrt{10} # #= -4 sqrt{10}#

# -4 \sqrt{90} + 2 \sqrt{160}#

# -4 \sqrt{3^2 cdot 10 } + 2 \sqrt{4^2 cdot 10}#

#= -12 sqrt{10} + 8 sqrt{10} #

#= -4 sqrt{10}#

Why does it say just asked when it's two years old?

enter image source here