Math, asked by rishu78655p2mu38, 1 year ago

help friend ques 7...

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Answered by rohitkumargupta
20
HELLO DEAR,

 \frac{ {7}^{3} }{ {7}^{(x - 2)} } = {7}^{7} \\ \\ \\ = {7}^{3} = {7}^{7} \times {7}^{x - 2} \\ \\ \\ = \frac{ 7 \times 7 \times 7 \times }{7 \times 7 } = {7}^{x - 2} \\ \\ \\ = > 7 = {7}^{x - 2} \\ \\ \\ = 1 = x - 2 \\ \\ \\ = x = 2 + 1 \\ \\ \\ = x = 3

second question,

9^x ÷ 9^-5 = 9^13

=> 9^2x × 1/9^-5 = 9^13

=> 9^2x × 9^5 = 9^13

=> 9^2x = 9^13/9^5

=> 9^2x = 9^8

HENCE ,

2x = 8

=> x = 4

I HOPE ITS HELP YOU DEAR,
THANKS

rohitkumargupta: :-)
Answered by TheAishtonsageAlvie
19
Heya user !!

Let me tell you few important Formula that I will

be using over here

 \frac{ {a}^{m} }{ {a}^{n \: } }  \:  =  {a}^{m - n}
Now coming to our Question -

(  \: i \: )  \:  \: \frac{ {7}^{3} }{ {7}^{x - 2} }  =  {7}^{7}  \\  \\  =  {7}^{3 - (x - 2)}  =  {7}^{7}  \\  \\  =  {7}^{3 - x + 2}  \:  =  {7}^{7}  \\  \\  =  - x + 5 \:  = 7 \\  \\   x =  - 2
Se know if the bases are the Same then its power are added


Now , Coming to the 2nd Question

ii) \:  \frac{ {9}^{2x} }{ {9}^{ - 5} }  =   {9}^{13 }  \\  \\  =   {9}^{2x + 5}  =  {9}^{13}  \\  \\  = >  x = 4


You may verify it by substituting the value of x

Thanks
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