In two binary linear equations, when the coefficient _ _ of the same unknown is equal to _ _ and _ is opposite to _ _, the unknown can be eliminated by subtracting _ _ or adding _ _ on both sides of the two equations respectively, and an _ _ _ _ _ equation can be obtained. This method is called.

2:

Solve the system of equations ① {y = x-37x+5y =-9; ② {3x+5y =123x-15y =-6 The simpler method is (c).

A. all use substitution method

B all use exclusion method.

C① substitution method, ② elimination method.

D ① exclusion method, ② substitution method.

3:

Equation set {8x-3y=9 8x+4y=-5 The equation obtained by eliminating x is (b).

A.y=4

B.-7y= 14

C.7y= 14

D.y= 14

4:

The system of equations {3x-2y = 6 12x-5y = 4② obtains (c) from ①×2-②×3.

A.3y=2

B.4y+ 1=0

C.y=0

D.7y= 10

5:

The optimal solution of the system of equations {3x-y =13x+2y =11② is (c).

A.y=3x-2 starts from ① and then brings it into ②.

B) 3x= 1 1-2y from ② and then into ①.

C. from ② to ①, eliminate X.

D.y is eliminated from ①×2+②.

6:

The solution of the system of equations {x+y=3 2x-y=6 is x = 3 and y = 0.

7:

Given that x and y satisfy the equation set {2x+y=5 x+2y=4, the value of x-y is _ _ _1_ _ _ _ _ _ _.

8:

The solution of binary linear equations {x+y=2 2x-y= 1 is (b).

A.{x=0 y=2

B.{x= 1 y= 1

C.{x=- 1 y=- 1

D.{x=2 y=0

9:

Given {3x=4+m, 2y-m=5, the relationship between x and y is (c).

A.3x+2y= 1

B.3x-2y= 1

C.3x-2y=- 1

D.3x-2y=9

10:

Equation set {x+y=5①, 2x+y= 10②, and the correct equation set from ②-① is (b).

A.3x= 10

B.x=5

C.3x=-5

D.x=-5

1 1:

Solve the equation {2x-3y=5① 3x-2y=7② by addition and subtraction. The following statement is incorrect (D).

A.①×3-②×2, excluding X.

B.①×2-②×3, eliminating Y.

C.①×(-3)+②×2, excluding X.

D.①×2-②×(-3), and eliminate Y.

12:

What if (x+y-5)? And |3y-2x+ 10| is the reciprocal, so the values of x and y are (d).

A.x=3，y=2

B.x=2，y=3

C.x=0，y=5

D.x=5，y=0