Question

If 5x+y = 625 and 5*-y = 25, then the value of y is :​

Answer 1

Answer:

5*x+y=5*4

5*x-y=2

x+y=4

x-y=2

2y=6

y=3

x=1 OK friend this is urs answer

Answer 2

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$\bullet \: \bf \: {5}^{x + y} = 625$

$\implies \bf \: {5}^{x + y} = {5}^{4}$

$\implies \bf \: x + y = 4 \: \: \: ....(1)$

$\bullet \bf \: {5}^{x - y} = 25$

$\implies \bf \: x - y = 2 \: \: \: \: ....(2)$

$\: \bullet \underline{ \pink{ \sf{ \: adding \: both \: equation \: (1) \: and \: (2)}}}$

$\implies \bf \: x + y = 4$

$\: \: \: \: \: \: \: \: \: \bf \: x - y = 2$

$\: \implies \sf \: 2x = 6$

$\implies \boxed{ \bf{x = 3}}$

$\: \bullet \underline{\pink{ \sf{put \: the \: value \: in \: equation \: (1)}}}$

$\implies \bf \: 3 + y = 4$

$\implies \boxed{ \bf{ \: y = 1}}$