We need to solve the following inequalities: (a) $10 - \sqrt{2x+7} \le 3$ (b) $3 \le \sqrt{2x+5} < 6$ (c) $\sqrt{2x+9} - \sqrt{9+x} > 0$ (d) $\sqrt{2} - \sqrt{x+6} \le -\sqrt{x}$ (e) $\sqrt{x-3} > \sqrt{x+4} - 1$ (f) $3 + \sqrt{2x-7} \le 6$

AlgebraInequalitiesRadicalsAlgebraic Manipulation
2025/5/11

1. Problem Description

We need to solve the following inequalities:
(a) 102x+7310 - \sqrt{2x+7} \le 3
(b) 32x+5<63 \le \sqrt{2x+5} < 6
(c) 2x+99+x>0\sqrt{2x+9} - \sqrt{9+x} > 0
(d) 2x+6x\sqrt{2} - \sqrt{x+6} \le -\sqrt{x}
(e) x3>x+41\sqrt{x-3} > \sqrt{x+4} - 1
(f) 3+2x763 + \sqrt{2x-7} \le 6

2. Solution Steps

(a) 102x+7310 - \sqrt{2x+7} \le 3
Subtract 10 from both sides:
2x+77-\sqrt{2x+7} \le -7
Multiply by -1 (and flip the inequality sign):
2x+77\sqrt{2x+7} \ge 7
Square both sides:
2x+7492x+7 \ge 49
Subtract 7 from both sides:
2x422x \ge 42
Divide by 2:
x21x \ge 21
Also, we need 2x+702x+7 \ge 0, so 2x72x \ge -7, which means x3.5x \ge -3.5.
Since x21x \ge 21, the condition x3.5x \ge -3.5 is satisfied.
(b) 32x+5<63 \le \sqrt{2x+5} < 6
Square all parts:
92x+5<369 \le 2x+5 < 36
Subtract 5 from all parts:
42x<314 \le 2x < 31
Divide by 2:
2x<15.52 \le x < 15.5
Also, we need 2x+502x+5 \ge 0, so 2x52x \ge -5, which means x2.5x \ge -2.5.
Since 2x<15.52 \le x < 15.5, the condition x2.5x \ge -2.5 is satisfied.
(c) 2x+99+x>0\sqrt{2x+9} - \sqrt{9+x} > 0
2x+9>9+x\sqrt{2x+9} > \sqrt{9+x}
Square both sides:
2x+9>9+x2x+9 > 9+x
Subtract 9 from both sides:
2x>x2x > x
Subtract x from both sides:
x>0x > 0
Also, we need 2x+902x+9 \ge 0, so 2x92x \ge -9, which means x4.5x \ge -4.5.
We also need 9+x09+x \ge 0, so x9x \ge -9.
Since x>0x > 0, the other two conditions are satisfied.
(d) 2x+6x\sqrt{2} - \sqrt{x+6} \le -\sqrt{x}
2+xx+6\sqrt{2} + \sqrt{x} \le \sqrt{x+6}
Square both sides:
(2+x)2x+6(\sqrt{2}+\sqrt{x})^2 \le x+6
2+22x+xx+62 + 2\sqrt{2x} + x \le x+6
22x42\sqrt{2x} \le 4
2x2\sqrt{2x} \le 2
Square both sides:
2x42x \le 4
x2x \le 2
Also, we need x+60x+6 \ge 0, so x6x \ge -6.
We also need x0x \ge 0.
So we have 0x20 \le x \le 2.
(e) x3>x+41\sqrt{x-3} > \sqrt{x+4} - 1
x3+1>x+4\sqrt{x-3} + 1 > \sqrt{x+4}
Square both sides:
(x3+1)2>x+4(\sqrt{x-3}+1)^2 > x+4
x3+2x3+1>x+4x-3 + 2\sqrt{x-3} + 1 > x+4
x2+2x3>x+4x-2 + 2\sqrt{x-3} > x+4
2x3>62\sqrt{x-3} > 6
x3>3\sqrt{x-3} > 3
Square both sides:
x3>9x-3 > 9
x>12x > 12
We need x30x-3 \ge 0, so x3x \ge 3.
We need x+40x+4 \ge 0, so x4x \ge -4.
Since x>12x>12, all conditions are satisfied.
(f) 3+2x763 + \sqrt{2x-7} \le 6
2x73\sqrt{2x-7} \le 3
Square both sides:
2x792x-7 \le 9
2x162x \le 16
x8x \le 8
We need 2x702x-7 \ge 0, so 2x72x \ge 7, which means x3.5x \ge 3.5.
So 3.5x83.5 \le x \le 8.

3. Final Answer

(a) x21x \ge 21
(b) 2x<15.52 \le x < 15.5
(c) x>0x > 0
(d) 0x20 \le x \le 2
(e) x>12x > 12
(f) 3.5x83.5 \le x \le 8