RS Aggarwal Solutions Class 8 Mathematics Solutions for Factorisation Exercise 7E in Chapter 7 - Factorisation

Question 3 Factorisation Exercise 7E

$x^3-144x=?$

$\text{ a. }x(x-12)^2$

$\text{ b. }x(x+12)^2$

c. x(x-12)(x+12)

d. none of these

Answer:

let us consider $\left(x^{3}-144 x\right)=x\left(x^{2}-144\right.$ ) by taking x as the common factor

By using the formula $a^{2}-b^{2}=(a-b)(a+b)$

= x (x – 12) (x + 12)

Video transcript

"hello students i am rita your math leader tutor and the today's question is x cube minus 144 x is equal to question mark and the options are a option x bracket x minus 12 whole square b option x bracket x plus 12 whole square and the c option x bracket x minus 12 x plus 12 and the d option none of these it is a mcq question and we have to find the correct option first of all the question is x cube minus 144 x now x we take x is common from both the terms then we got x square minus 144 as we know 100 we can write x square as x whole square and minus 144 is the perfect whole square of 12 so we can write it as 12 square as we know the identity that is a square minus b square is equal to a plus b a minus b now we use this identity in the question and we got the answer so when we use this identity then we got x plus 12 and x minus 12 now this is the answer of this question and the c option is the correct answer so c option is the answer i hope you like this video so please subscribe for more updates and do comment your question thank you "

Related Questions

a) (7a – 9b) (9a + 7b)b) (7a – 9b) (7a + 9b)c) 9(a – 3b) (a + 3b)d) 7(a – 3b) (a + 3b)

a. 2(x-4)(x+4d. 2x(1-4x)(1+4x)

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a. (pq+1)(q-1)b. p(q+1)(q-1)c. q(p-1)(q+1)d. (pq-1)(q+1)

ab –mn +an –bm = ?a. (a-b) (m-n)b. (a-m) (b+n)c. (a-n) (m+b)d. (m-a) (n-b)

Exercises

Factorisation Exercise 7A

Factorisation Exercise 7B

Factorisation Exercise 7C

Factorisation Exercise 7D