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