Question

алгебра:{7^7x-y=7^-2{-2x+y=7​

Answer 1

{7^7x-y=7^-2

{-2x+y=7

{7^7x-(7+2x)=7^-2

{y=7+2x

{7x-7-2x=-2

{y=7+2x

{5x=5

{y=7+2x

{x=1

{y=7+2*1

{x=1

{y=9

Ответ: x=1; y=9 либо (x,y)=(1,9)

Answer 2

${7}^{7x - y} = {7}^{ - 2} \\ -2x+y=7 \\ \\ 7x - y = - 2 \\ - 2x + y = 7 \\ \\ 7x - 2x- y + y= - 2 + 7 \\ 5x = 5\\ x = 1 \\ y = 7 + 2x\\ y = 7 + 2 \times 1 = 9$

ответ: (1; 9)