Can You Make This Complex Calculation Simple?

Algebra Level 1

Evaluate

50 0 3 8 50 0 2 + 2 × 500 + 4 . \frac{ 500^3 - 8 } { 500^2 + 2 \times 500 + 4}.

Details and assumptions

This problem was originally posed by Gabriel M .


The answer is 498.

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8 solutions

Benjamin Kan
Sep 29, 2013

First, we see that 8 = 2 3 8=2^3 .By factoring 50 0 3 2 3 500^3-2^3 , we get ( 500 2 ) ( 50 0 2 + 2 500 + 2 2 ) (500-2)(500^2+2*500+2^2) . We notice that ( 50 0 2 + 2 500 + 2 2 ) (500^2+2*500+2^2) is the same as the denominator, so we can divide that out leaving us just with 500 2 = 498 500-2=\boxed{498}

u clear my dout sir thanxx

Manoj Kumar - 7 years, 8 months ago

wowwww!!

Saikarthik Bathula - 7 years, 8 months ago

woow talaga

Jeremy Deleon - 7 years, 8 months ago
Daniel Chiu
Sep 29, 2013

Let a = 500 a=500 , b = 2 b=2 . Then, we must find a 3 b 3 a 2 + a b + b 2 \dfrac{a^3-b^3}{a^2+ab+b^2} However, we know the difference of cubes factorization , which says that ( a b ) ( a 2 + a b + b 2 ) = a 3 b 3 (a-b)(a^2+ab+b^2)=a^3-b^3 Therefore, the answer is a b = 500 2 = 498 a-b=500-2=\boxed{498} .

Thank you Dan.

Rendy Nainggolan - 7 years, 8 months ago

Quick unrelated note: There's also the "Difference of three cubes" factorization which is a 3 + b 3 + c 3 3 a b c = ( a + b + c ) ( a 2 + b 2 + c 2 a b b c c a ) = 1 2 ( a + b + c ) ( ( a b ) 2 + ( b c ) 2 + ( c a ) 2 ) a^3+b^3+c^3-3abc=(a+b+c)(a^2+b^2+c^2-ab-bc-ca)=\frac{1}{2}(a+b+c)((a-b)^2+(b-c)^2+(c-a)^2) . Note how this also proves the 3-variable AM-GM.

Arkan Megraoui - 7 years, 6 months ago
Victor Loh
Jan 4, 2014

Note that

50 0 3 8 500^{3}-8

= 50 0 3 2 3 = 500^{3}-2^{3}

= ( 500 2 ) ( 50 0 2 + 2 × 500 + 2 2 ) = (500-2)(500^{2}+2 \times 500 + 2^{2})

= ( 500 2 ) ( 50 0 2 + 2 × 500 + 4 ) = (500-2)(500^{2} + 2 \times 500 + 4)

Hence,

50 0 3 8 50 0 2 + 2 × 500 + 4 \dfrac{500^{3}-8}{500^{2}+2 \times 500 + 4}

= ( 500 2 ) ( 50 0 2 + 2 × 500 + 4 ) 50 0 2 + 2 × 500 + 4 = \dfrac{(500-2)(500^{2}+2 \times 500 + 4)}{500^{2}+2 \times 500 + 4}

= 500 2 = 500 -2

= 498 = \boxed{498}

Alex Benfield
Sep 30, 2013

Calculator.

lol

Arkan Megraoui - 7 years, 6 months ago

STOP.SPAMMING.

Akshat Prakash - 7 years, 8 months ago
Aakash Jain
Sep 30, 2013

(500^3-2^3)/(500^2+2 500+2^2)=(500-2)(500^2+2 500+2^2)/ (500^2+2*500+2^2)=500-2=498 here we use the identity (a^3-b^3)=(a-b)(a^2+ab+b^2)

Larry John
Sep 30, 2013

500^3 - 8=124999992 500^2+2*500+4=251004 124999992/251004=498

i m also do like that

Manoj Kumar - 7 years, 8 months ago
Raj Kumar
Jan 8, 2014

(500^3-8)/500^2+2 500+4), here, (500^3-8) is to be (500^3-2^3) like this so expansion of a^3-b^3 is (a-b)(a^2+ab+b^2) in this way this sum write like this (500-2)(500^2+2 500+4)/(500^2+2*500+4) so cancel remaining (500-2) result is 498

2500 is error 2*500 is correct

Raj Kumar - 7 years, 5 months ago
Sonu Sekar
Oct 2, 2013

answer for this problem:

Nu:500cube-8=(500 500 500)-8=125000000-8=124999992

De:500square+2 100+4=(500 500)+1000+4=250000+1004=251004

Nu/De=124999992-251004=498

I could not understand this process

Vikrant Adhikary - 6 years, 9 months ago

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