5/7 = x/(21)

解答

\frac{5}{7} = \frac{x}{21}

x = 15

求解步骤

\frac{5}{7} = \frac{x}{21}

交换两边

\frac{x}{21} = \frac{5}{7}

在两边乘以

21

x = 15

\frac{5}{2} (x - 2) - \frac{3}{4} (x + 4) \geq - 2

- 2 x^{2} - 5 x = 0

3 w + 3 (2 w - 10) \geq 10 w - 6 - 1

s im pl i f y \frac{\frac{5}{2}}{\frac{3}{2}}

\frac{4}{3} x < - 8