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Register now and save up to $200 Available with Beat the GMAT members only code • Free Practice Test & Review How would you score if you took the GMAT Available with Beat the GMAT members only code • 5 Day FREE Trial Study Smarter, Not Harder Available with Beat the GMAT members only code • Get 300+ Practice Questions 25 Video lessons and 6 Webinars for FREE Available with Beat the GMAT members only code • Magoosh Study with Magoosh GMAT prep Available with Beat the GMAT members only code • 5-Day Free Trial 5-day free, full-access trial TTP Quant Available with Beat the GMAT members only code • Free Trial & Practice Exam BEAT THE GMAT EXCLUSIVE Available with Beat the GMAT members only code ## Functions This topic has 3 member replies jayanti Senior | Next Rank: 100 Posts Joined 19 Apr 2011 Posted: 72 messages Followed by: 5 members #### Functions Fri Aug 05, 2011 4:22 am Elapsed Time: 00:00 • Lap #[LAPCOUNT] ([LAPTIME]) The function f is defined by f(x) = √x - 10 for all positive numbers x. If u = f(t) for some positive numbers t and u. What is t in terms of u? A. √(u+10) B. (√u + 10)^2 C. √(u^2+10) D. (u + 10)^2 E. (u^2 + 10)^2 Need free GMAT or MBA advice from an expert? Register for Beat The GMAT now and post your question in these forums! knight247 Legendary Member Joined 19 Apr 2011 Posted: 504 messages Followed by: 10 members Thanked: 114 times Target GMAT Score: 800 Fri Aug 05, 2011 4:41 am f(x)=√x - 10 f(t)=√t - 10 Also, u=f(t) u=√t - 10 √t=u+10 t=(u+10)^2 Hence D gmatboost Master | Next Rank: 500 Posts Joined 02 Aug 2011 Posted: 312 messages Followed by: 33 members Thanked: 130 times Test Date: June, 2006 GMAT Score: 780 Fri Aug 05, 2011 10:21 am You can also plug in for t, find u, and then check the answers. Say, t = 9 (pick a square since we need to take the square root). u = f(t) = √t - 10 = √9 - 10 = 3 - 10 = -7 Now you can plug in u = -7 and see which answer gives you t = 9. _________________ Greg Michnikov, Founder of GMAT Boost GMAT Boost offers 250+ challenging GMAT Math practice questions, each with a thorough video explanation, and 100+ GMAT Math video tips, each 90 seconds or less. It's a total of 20+ hours of expert instruction for an introductory price of just$10.
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Sat Aug 06, 2011 3:26 pm
u = f(t) = √t - 10

(u+10)^2 = t

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