1
00:00:00,720 --> 00:00:04,970
题目问我们找到

2
00:00:04,970 --> 00:00:06,600
-2f(-6)+g(1)的值。

3
00:00:06,600 --> 00:00:08,460
f(x)和g(x)

4
00:00:08,460 --> 00:00:10,757
是下面图里的两个函数。

5
00:00:10,757 --> 00:00:12,340
让我们看看我们如何求这个值。

6
00:00:12,340 --> 00:00:14,270
好的我们先要找到

7
00:00:14,270 --> 00:00:16,540
f(-6)的值是什么。

8
00:00:16,540 --> 00:00:19,760
所以x值是-6.

9
00:00:19,760 --> 00:00:22,420
这个是在横坐标轴上。

10
00:00:22,420 --> 00:00:24,110
让我们输入-6.

11
00:00:24,110 --> 00:00:26,850
根据图示，

12
00:00:26,850 --> 00:00:30,010
f(-6)等于7

13
00:00:30,010 --> 00:00:30,890
所以这就是f(-6)

14
00:00:30,890 --> 00:00:35,690
让我写下来。f(-6)=7

15
00:00:35,690 --> 00:00:36,970
那么g(1)?

16
00:00:39,910 --> 00:00:42,890
再一次，让我们输入x值。

17
00:00:42,890 --> 00:00:45,410
就是g(1),

18
00:00:45,410 --> 00:00:48,660
就是这里，也就是-5.

19
00:00:48,660 --> 00:00:51,920
g(1)=-5.

20
00:00:51,920 --> 00:00:57,240
这个式子就可以简化成-2乘以

21
00:00:57,240 --> 00:00:59,700
f(-6)就是7.

22
00:00:59,700 --> 00:01:07,265
所以7加上g(1),也就是-5.

23
00:01:07,265 --> 00:01:12,580
再加上-5，就简化成了---让我看一下。

24
00:01:12,580 --> 00:01:17,900
-2乘以7等于-14加上-5，

25
00:01:17,900 --> 00:01:20,200
也就是-19

26
00:01:20,200 --> 00:01:22,660
我们就做完了。