Question

допустимо: (3a -5b)÷(a +3b)= a+3b не равно нулю

Answer 1

$frac{3a - 5b}{a + 3b} = a + 3b \ \ frac{3a - 5b}{a + 3b} - a - 3b = 0 \ \ frac{3a - 5b}{a + 3b} - frac{a {}^{2} - 9b {}^{2} }{a + 3b} = 0 \ \ frac{3a - 5b - a {}^{2} - 9b {}^{2} }{a + 3b} = 0 \ \ frac{3a - 5b - (a - 3b)(a + 3b)}{a + 3b} = 0 \ \ 3a - 5b - a + 3b = 0 \ \ 2a - 2b = 0 \ \ 2(a - b) = 0 \ \ 2a = 2b \ \ a = b$
a=b, b € R