Algebraic expression and identities:
Evaluate using identities:
(8.9)2[this for the whole square mark]
(0.9)2
[Urgent plz give me the answer with all steps and explanation on how to do because i am confused]
hajerabanu11:
Can anyone give an answer fast plz
Its really urgent
Answers
Answered by
2
Hii...
consider,
we gave 89 instead of 8.9
by using (x+y)^2=x^2+2xy+y^2
(80+9)^2=6400+1440+81
=====7921
8.9^2===79.21
then,
9^2=(10-1)
10^2-2*10*1+1^2
==100-20+1
====81
now ,
0.9^2=8.1
consider,
we gave 89 instead of 8.9
by using (x+y)^2=x^2+2xy+y^2
(80+9)^2=6400+1440+81
=====7921
8.9^2===79.21
then,
9^2=(10-1)
10^2-2*10*1+1^2
==100-20+1
====81
now ,
0.9^2=8.1
But can u explain in this way like i have the answer but dont understand
soo (9.9)^2
ans=(10-0.1)=(10)^2 - 2(10)(0.1) +(0.1)^2=[then i dont know]
Actually i just understood ur answer
I still cant understand
Plz explain
Answered by
1
Here is your answer :
We can solve this problem using - [a - b]^2 = a^2 - 2ab + b^2
1. 8.9^2
8.9 = 9 - 0.1
8.9^2 = [ 9 - 0.1 ]^2
8.9^2 = 9^2 - 2 × 9 × 0.1 + 0.1^2
= 81 - 0.18 + 0.01
= 79.21 [Ans]
2. 0.9^2
0.9 = 1 - 0.1
0.9^2 = [ 1 - 0.1 ]^2
0.9^2 = 1^2 - 2 × 1 × 0.1 + 0.1^2
= 1 - 0.2 + 0.01
= 0.81. [ Ans]
Hope you got your answer. ☺☺
We can solve this problem using - [a - b]^2 = a^2 - 2ab + b^2
1. 8.9^2
8.9 = 9 - 0.1
8.9^2 = [ 9 - 0.1 ]^2
8.9^2 = 9^2 - 2 × 9 × 0.1 + 0.1^2
= 81 - 0.18 + 0.01
= 79.21 [Ans]
2. 0.9^2
0.9 = 1 - 0.1
0.9^2 = [ 1 - 0.1 ]^2
0.9^2 = 1^2 - 2 × 1 × 0.1 + 0.1^2
= 1 - 0.2 + 0.01
= 0.81. [ Ans]
Hope you got your answer. ☺☺
How do u do the calculation for 81-0.81+0.01 thats the only step i cant understand
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