X{ multiplication sign}
2 13 . x > 3 | 14.3 | 15。 It shouldn't be necessary. | 16.m < 0 | 17。 -2 | 18.45 | 18.
Third, the calculation problem: (do not copy the problem) 2 1.
X > half
Derive from ②
X < 2。 The solution set is
Half < x < 222.x < 1。 |
23. suppose you can buy x copies. Formula: 65
X (times) 20
+
40X≤2000
X≤ 17 and 1/2. A: Buy at most 17 copies. 24.( 1)b
+
200a
= 1400; b
+
150a
=
1250
a = 3； B=800(2) sets with at least x copies. |
Column type: 800
+
3X
≥
One thousandth. A: At least 334. 25.( 1) form, from left to right,+,-,+(2)-2 < x