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Surds

I just want to clarify whether my answer is correct for this question....

Fully simplify:
√72 + √8

√9√8 + √8 = 3+2√8?

Thanks
Reply 1
Avatar for Xzerzes
Xzerzes
10
8 root 2
4 root 8 or 8 root 2 again
Reply 2
Avatar for RosaA
RosaA
OP
4
Original post by Xzerzes
8 root 2
4 root 8 or 8 root 2 again


Thanks! My answer was wrong then :colondollar:

√72 + √8 =

√36 √2 + √4 √2
6 √2 + 2 √2

Is this correct so far?
Reply 3
Avatar for Xzerzes
Xzerzes
10
√72= √36x2 so = 6√2 √8= 2√2 so overall you get 8√2

√9√8 + √8 can be either √72 +√8 getting 8√2 again or you can just use the √9√8 and simplify to 3√8 + √8 =4√8

so what you've done for the first one is correct :smile:
Reply 4
Avatar for Zacken
Zacken
22
Original post by RosaA
Thanks! My answer was wrong then :colondollar:

√72 + √8 =

√36 √2 + √4 √2
6 √2 + 2 √2

Is this correct so far?


Yes, but do you agree that 6x+2x=8x6x + 2x = 8x? So 62+22=2(6+2)=826\sqrt{2} + 2\sqrt{2} = \sqrt{2} (6 + 2) = 8\sqrt{2}.
Reply 5
Avatar for RosaA
RosaA
OP
4
Original post by Zacken
Yes, but do you agree that 6x+2x=8x6x + 2x = 8x? So 62+22=2(6+2)=826\sqrt{2} + 2\sqrt{2} = \sqrt{2} (6 + 2) = 8\sqrt{2}.


Yes I agree.... okay cool got it, haha. Thank you :biggrin:

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