OCR Surds (again.. diff question)

Solve the following equation, giving your answer in the form of

k \sqrt 2

z\sqrt {32} - 16 = z\sqrt {8} - 4

The answer is

z = 3\sqrt {2}

Can somebody pls show me how you worked it out,

Thanks

Reply 1

Gemini92

Original post by Bleak Lemming

Solve the following equation, giving your answer in the form of

k \sqrt 2

z\sqrt {32} - 16 = z\sqrt {8} - 4

The answer is

z = 3\sqrt {2}

Can somebody pls show me how you worked it out,

Thanks

First gather the terms containing z on one side and the ones that don't on the other. Then rewrite the surds and multiples of sqrt2 and take a factor of z out and rearrange to make z the subject.

Reply 2

JoMo1

12

Take your Zs to one side, and your numbers to the other. Factorize out your Zs on the Z side (so you get Z*(something-something)) then you can figure out the surds in the bracket and then solve it like any other linear equation.

Reply 3

Bleak Lemming

OP

16

Original post by JoMo1

Take your Zs to one side, and your numbers to the other. Factorize out your Zs on the Z side (so you get Z*(something-something)) then you can figure out the surds in the bracket and then solve it like any other linear equation.

Original post by Rup

oks

Ok I've got as far as

z (4\sqrt{2} - 2\sqrt{2}) = 12[br][br]z(2\sqrt{2}) = 12[br][br]2z\sqrt{2} = 12[br][br]z\sqrt{2} = 6

This isn't going the right way here :s

(edited 13 years ago)

Reply 4

Gemini92

Original post by Bleak Lemming

Ok I've got as far as

z (4\sqrt{2} - 2\sqrt{2}) = 12[br][br]z (2\sqrt{2}) = 12[br][br]2z\sqrt{2} = 12[br][br]z\sqrt{2} = 6

This isn't going the right way here :s

That's right now divide through by sqrt2, remembering that 6=3x2 and 2/sqrt2=sqrt2.

Reply 5

LeeC

15

I got the answer as 6/root 2, which works.

Reply 6

reaped

Original post by Bleak Lemming

Ok I've got as far as

z (4\sqrt{2} - 2\sqrt{2}) = 12[br][br]z(2\sqrt{2}) = 12[br][br]2z\sqrt{2} = 12[br][br]z\sqrt{2} = 6

This isn't going the right way here :s

yeah it is lol

Reply 7

Bleak Lemming

OP

16

Original post by Gemini92

That's right now divide through by sqrt2, remembering that 6=3x2 and 2/sqrt2=sqrt2.

Thanks!

got there in the end :]

Reply 8

Rup

6

C1 is nothing to worry abt....its jus apiece of cake! Whats really tough for me was Stats! however my hard work paid off at the end! Right now i m standing proud with an overall A in Maths, hehe!

OCR Surds (again.. diff question)

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