Question

составьте обратную функцию к функции у= -2х+7

Answer 1

y = f(x) = -2x+7,
y+2x = 7,
2x = -y+7,
x = (7-y)/2,
z = z(t) = (7-t)/2,
обратная функция g(t) = (7-t)/2.
проверка f(g(x)) = -2*g(x) + 7 = -2*( (7-x)/2) + 7 = -(7-x) + 7 = x.
g(f(x)) = (7-f(x))/2 = (7 - (-2x+7))/2 = (7+2x-7)/2 = 2x/2 = x.