Book Online Demo

Check Your IQ

Try Test

Courses

Dropper NEET Course Dropper JEE Course Class - 12 NEET Course Class - 12 JEE Course Class - 11 NEET Course Class - 11 JEE Course Class - 10 Foundation NEET Course Class - 10 Foundation JEE Course Class - 10 CBSE Course Class - 9 Foundation NEET Course Class - 9 Foundation JEE Course Class -9 CBSE Course Class - 8 CBSE Course Class - 7 CBSE Course Class - 6 CBSE Course

Offline Centres

Factorise the expression $28 − 31 x − 5 x 2$ .

see full answer

Talk to JEE/NEET 2025 Toppers - Learn What Actually Works!

Real Strategies. Real People. Real Success Stories - Just 1 call away

An Intiative by Sri Chaitanya

x + 7 4 − 5 x

x − 7 4 − 5 x

x + 7 4 + 5 x

None of these

answer is A.

(Unlock A.I Detailed Solution for FREE)

Ready to Test Your Skills?

Check your Performance Today with our Free Mock Test used by Toppers!

Take Free Test

Detailed Solution

Given expression is

28 − 31 x − 5 x 2

.
This can be rewritten as:

28 − 31 x − 5 x 2 = − 5 x 2 + 31 x − 28

To factorise the given expression, taking the product of the coefficient of

x 2

with the constant term where constant term is 28 and coefficient of

is 5,

⇒ 5 × 28 = 140

Now, finding the factors of

140

and treat them as the coefficient of x.

⇒ 140 = 35 × 4

Now, subtracting the factors,

⇒ 35 − 4 = 31

So, the expression can be written as:
Question Image

Therefore, the factors of the given expression are

x + 7 and 4 − 5 x

.
Thus, the factorisation of

.
Hence, option 1 is correct.

Watch 3-min video & get full concept clarity

Result Producing online coaching for JEE/NEET of south India

Largest All India Test Series for JEE/NEET

Best Online Course for IIT JEE

Best Online Course for NEET

Best Online Course for CBSE

Best Courses for You

JEE

NEET

Foundation JEE

Foundation NEET

CBSE

Get Expert Academic Guidance – Connect with a Counselor Today!