1) 7a = 12a - 2) 4/x = 2/7 3) 1/3 = 1 4) 2.7 \cdot 1.5 = 5) 1/3 \cdot (-45) = 3/5 6) 2.2 - 2.5 / (1.1 - 0.5) 7) m2/V2 = m1/V1 8) 4 = a + 3x

Решение:

• 1) \(7a = 12a - \Rightarrow 12a - 7a = 0 \Rightarrow 5a = 0 \Rightarrow a = 0\)
• 2) \(\frac{4}{x} = \frac{2}{7} \Rightarrow 2x = 4 \cdot 7 \Rightarrow 2x = 28 \Rightarrow x = 14\)
• 3) \(\frac{1}{3} = 1\) — данное равенство неверно, так как \(\frac{1}{3}
  eq 1\).
• 4) \(2.7 \cdot 1.5 = 4.05\)
• 5) \(\frac{1}{3} \cdot (-45) = \frac{-45}{3} = -15\). Равенство \(-15 = \frac{3}{5}\) неверно.
• 6) \(\frac{2.2 - 2.5}{1.1 - 0.5} = \frac{-0.3}{0.6} = -0.5\)
• 7) \(\frac{m_2}{V_2} = \frac{m_1}{V_1} \Rightarrow m_1 = \frac{m_2 V_1}{V_2}\)
• 8) \(4 = a + 3x \Rightarrow 3x = 4 - a \Rightarrow x = \frac{4-a}{3}\)

Ответ:

• 1) a = 0
• 2) x = 14
• 3) Равенство неверно
• 4) 4.05
• 5) Равенство неверно
• 6) -0.5
• 7) \(m_1 = \frac{m_2 V_1}{V_2}\)
• 8) \(x = \frac{4-a}{3}\)