1、B? 2、C? 3、D4,2
5、k=-4,{x=- 1? Y=-3 is not the solution of this equation.
6{ 1}b= 16-4a/3? {2} When a =-2,0 and 1, the corresponding values of b are 8,16/3,4 respectively.
Binary linear equations
1、A? 2、D3、D4、8
5. Let the number of people going to Beijing be X and the number of people going to Emperor Island be Y. According to the meaning of the question, {X+Y = 128X = 2Y- 1.
Solving binary linear equations
1、D2、C3、A? 4、2x=-4? 5、①,y=-2x+3,②, 1, 1,{x= 1,y = 16 ,{ x = 2,y=- 17 ,{ x = 1,y =- 1
Communication and inquiry
The record is wrong. Reason: a toothbrush is X yuan, and a box of toothpaste is Y yuan. According to the meaning of the question, {39x+21y = 396,52x+28y = 518 is simplified, and this equation is {13x+7y = 132,13x+7y.
Test questions of binary linear equations [8. 1, 8.2]
1. 1,A2。 b? 3.c? 4.c? 5.b? 6.d? 7.C8.B? 9.A 10。 B
Two. 1 1.5,2 12.2[2x+y]= 10 13。 1/4? 14.? 3-x/3,3-3y 15.23/2 16。 The answer is not unique, such as {x+y =- 1? x-y=3 17。 -4? 18? {x= 1? y=3? {x=2? y= 1 19.9? 20.{2x-3y= 16x+y= 1
3.2 1. From the meaning of the question, {2m+3 = 1, 5n-9 = 1, {m =- 1? n=2? ∴m square +n square = [- 1] square +2 square =5.
22. In terms of meaning, {-2-3m = 7, -n+9 =-4? The solution is {m =-3? n= 13∴3m-4n=3x〔-3〕-4x 13=-6 1
Look at the picture below