solve ques 12,13,14
Answers
14. 7m-7=20
7m=20+7
7m=27
m=27÷7
m = 3.86.
12. Let, 0.363636... = x ............ (1)
Multiplying both sides by 100,
36.363636... = 100x ............ (2)
In subtracting (1) from (2),
99x = (36.363636...)—(0.363636...)
99x=36
x=36/99
x=4/11
0.3636..=4/11
13. {(-3/7)² / (3/7)²}¯³
= {(-3/7)² × (7/3)²}¯³
=(1)¯³ [Everything is cancelled out, (-3)² is squared, so we won't get (-1),we'll get 1 instead, in the bracket]
=1/1³
=1
14.
7(m-1)=20
7m-7=20
7m=20+7
7m=27
m=27/7
Verification : Putting value of m in the given equation, we get,
7(27/7-1)=20
7(27/7-7/7)=20
7(20/7)=20
7 and 1/7 are cancelled,
20=20
L. H. S = R. H. S.
Verified!!
Hope it helps!!
In the 4th step of Q. 13, we get 1 instead of - 1, because the negative (-3)² in the bracket is squared, so it'll eventually become positive on solving.
