LIVE Course for free

Rated by 1 million+ students
Get app now
Class 8 Foundation Course
Class 9 Foundation Course
Class 10 Foundation Course
Class 11 Foundation Course
Class 12 Foundation Course
JEE COURSE
NEET COURSE
0 votes
17 views
in Aptitude by (54.3k points)
closed by
If a - b = 4 and ab = 21, find the value of a3 - b3
1. 302
2. 316
3. 304
4. 296

1 Answer

0 votes
by (30.0k points)
selected by
 
Best answer
Correct Answer - Option 2 : 316

Given:

a - b = 4 and ab = 21

Formula Used:

a+ b2 = (a - b)2 + 2ab

a3 - b3 = (a - b)(a2 + b2 + ab)

Calculation:

As, a - b = 4 and ab = 21

Now, a+ b2 = (4)2 + 2 × 21 = 16 + 42 = 58

a3 - b3 = (4)(58 + 21) = 4 × 79 = 316

∴ The value of a3 - b3 is 316.

Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students.

Categories

...