3) Реши уравнения: a) (x+4)/64 = (4x-6)/9; б) -2/3 - 2/3 = (4x-6)/(9(x-3))

а) (x+4)/64 = (4x-6)/9

• Приведем к общему знаменателю (576):
• $$9(x+4) = 64(4x-6)$$
• $$9x + 36 = 256x - 384$$
• $$36 + 384 = 256x - 9x$$
• $$420 = 247x$$
• $$x = \frac{420}{247}$$

б) -2/3 - 2/3 = (4x-6)/(9(x-3))

• $$-4/3 = (4x-6)/(9(x-3))$$
• $$-4  9(x-3) = 3(4x-6)$$
• $$-36(x-3) = 12x - 18$$
• $$-36x + 108 = 12x - 18$$
• $$108 + 18 = 12x + 36x$$
• $$126 = 48x$$
• $$x = \frac{126}{48}$$
• $$x = \frac{21}{8}$$

Ответ: а) x = 420/247; б) x = 21/8