Chapter 4
Exploring Algebraic Identities
CBSE Class 9
Mathematics Solutions
Educart Mathematics class Class 9 NCERT Exemplar cover
Question:

Try to simplify the following rational expression:

36s212st+t2t2+2ts48s2=(6st)2(_+_)(_+_)\frac{36s^2 - 12st + t^2}{t^2 + 2ts - 48s^2} = \frac{(6s - t)^2}{(\_ + \_)(\_ + \_)}

(Hint: Factor t2+2ts48s2t^2 + 2ts - 48s^2 and simplify the rational expression, assuming that $t^2 + 2ts - 48s^2
eq 0$.) [Page No. 85]

Answer: Verified

Factor the numerator: 36s212st+t236s^2 - 12st + t^2

=(6st)2=(t6s)2.= (6s - t)^2 = (t - 6s)^2.

Factor the denominator: t2+2ts48s2t^2 + 2ts - 48s^2

=(t+8s)(t6s),= (t + 8s)(t - 6s),

since 8s8s and 6s-6s add to 2s2s and multiply to 48s2-48s^2.

Substituting these factors,

36s212st+t2t2+2ts48s2=(t6s)2(t+8s)(t6s)\frac{36s^2 - 12st + t^2}{t^2 + 2ts - 48s^2} = \frac{(t - 6s)^2}{(t + 8s)(t - 6s)}

Cancelling the common factor (t6s)(t - 6s), t6st+8s\frac{t - 6s}{t + 8s}

Hence, the blanks are (t+8s)(t6s)(t + 8s)(t - 6s).

This simplification is valid provided $t^2 + 2ts - 48s^2
eq 0$.

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