第5章 5.8

(1)

$4x + 3 < 11 \qquad 4x < 8 \qquad x < 2$

(2)

$-3x + 2 > 5 \qquad -3x > 3 \qquad 3x < -3 \qquad x < -1$

(3)

$5x - 2 > 2x - 8 \qquad 3x > -6 \qquad x > -2$

(4)

$x - 5 \geq 3x + 7 \qquad -2x \geq 12 \qquad 2x \leq -12 \qquad x \leq -6$

(5)

$\frac{2x+1}{3} \leq \frac{2x-1}{2} \qquad 2(2x+1) \leq 3(2x-1) \qquad 4x+2 \leq 6x-3 \qquad 2x \geq 5 \qquad x \geq \frac{5}{2}$

(6)

$3x + \frac{x+1}{5} \leq \frac{6-4x}{15} \qquad 45x + 3(x+1) \leq 6 - 4x \qquad 52x \leq 3 \qquad x \leq \frac{3}{52}$

(7)

$0.2x + 5 < x - 3 \qquad -0.8x < -8 \qquad 0.8x > 8 \qquad x > 10$

(8)

$0.3(x+1) + 0.1x > 0.2(1+2x) \qquad 3(x+1) + x > 2(1+2x) \qquad 0x > -1 \qquad \text{よって全ての実数が解となる}$