If x^2 − 5x − 6 = 0, which of the following could be x ? GMAT Problem Solving

Question: If x^2 − 5x − 6 = 0, which of the following could be x ?

1. −2
2. −1
3. 1
4. 2
5. 3

‘If x^2 − 5x − 6 = 0, which of the following could be x ?’ - is a topic of the GMAT Quantitative reasoning section of GMAT. This question has been taken from the book “The Official Guide for GMAT Reviews”. To solve GMAT Problem Solving questions a student must have knowledge about a good amount of qualitative skills. The GMAT Quant topic in the problem-solving part requires calculative mathematical problems that should be solved with proper mathematical knowledge.

Solution and Explanation:

Approach Solution 1:
Given in the question an equation,

\(x^2\) -5x - 6 = 0
It has asked that which of the following options could be the value of x.
The equation given is

\(x^2\) - 5x - 6 = 0

\(x^2\)-( 6x-x) -6 = 0 (middle term split)

\(x^2\) - 6x +x - 6 = 0

x(x - 6) +(x - 6) = 0
(x-6)(x+1) = 0

The only values of x for which this equation is 0 is –
X = -1, 6
In the given options only option B matches the value of x
Therefore B is the correct answer.

Correct Answer: B

Approach Solution 2:

Given in the question
an equation,
x^2 -5x - 6 = 0
It has asked which of the following options could be the value of x.
The equation given is

\(x^2\)- 5x - 6 = 0

Using quadratic formula,

X = (\(-b {\pm} \sqrt{b^2-4ac}\))/2a

Here the values of b = -5
A = 1
And c = -6

X = (\(-(-5){\pm}\sqrt{(-5)^2-4*1*(-6)}\) ) / 2.1

X = (5 \({\pm}\sqrt{25+24}\))/2

X = (5\(\pm\sqrt49\))/2

X = (5\(\pm\) 7)/2

X = (5+7)/2 , (5-7)/2

X = 6,-1

Only option B contains one of the roots of x
The correct answer will be option B.

Correct Answer: B

Approach Solution 3:

Given: x^2–5x–6=0
To find: What could be the value of x among the given choices
Then the equation further can be solved as:

x^2–5x–6=0
This implies x^2–6x+x–6=0
This implies (x – 6) * (x + 1) = 0
Therefore, x = -1 or 6

Hence, the correct answer is Option B.

Correct Answer: B

Suggested GMAT Problem Solving Questions

• A Man has 1044 Candles. After Burning, He can Make a New Candle GMAT Problem Solving
• An Equilateral Triangle ABC is Inscribed in Square ADEF GMAT Problem Solving
• A Popular Website Requires Users to Create a Password Consisting of Digits Only GMAT Problem Solving
• A Furniture Store Sells Only Two Models of Desks, Model A and Model B GMAT Problem Solving
• In a Drawer, There are 4 White Socks, 3 Blue Socks, and 5 Grey Socks GMAT Problem Solving
• There are 100 Apples in a Bag of which 98% are Green and Rest are Red GMAT Problem Solving
• A palindrome is a number that reads the same forward and backward GMAT Problem Solving
• Three Cars Leave From A To B In Equal Time Intervals GMAT Problem Solving
• An Inlet Pipe can Fill in an Empty Cistern in 30 minutes GMAT Problem Solving
• Iqbal Dealt Some Cards to Mushtaq and himself from a Full Pack of Playing Cards GMAT Problem Solving
• A Zookeeper Counted the Heads of the Animals in a Zoo and Found it to be 80 GMAT Problem Solving
• A Shop Stores x kg of Rice. The First Customer Buys half this Amount Plus half a kg of Rice GMAT Problem Solving
• In a Class of 120 Students Numbered 1 to 120, All Even Numbered Students Opt for Physics GMAT Problem Solving
• Machine A Produces bolts at a Uniform Rate of 120 Every 40 seconds GMAT Problem Solving
• Out of 7 Consonants and 4 Vowels, How Many Words of 3 Consonants and 2 Vowels Can be Formed? GMAT Problem Solving
• 4 Bells Toll Together at 9:00 A.M. They Toll After 7, 8, 11 and 12 Seconds GMAT Problem Solving
• 12 Marbles are Selected at Random from a Large Collection of White, Red, Green and Yellow Marbles GMAT Problem Solving
• Find the greatest number that will divide 43, 91 and 183 GMAT Problem Solving
• Of the 150 Houses in a Certain Development GMAT Problem Solving
• A man can hit a target once in 4 shots. If he fires 4 shots in succession GMAT Problem Solving