{4 (x + 2) = 1-5y, 3 (y + 2) = 3-2x {2 / y + 3 / x = 13,3 / y-4 / x = 3 {x + y = 420,30% x + 40% y = 160 * 80% the equations are solved by addition subtraction elimination method

{4(x+2)=1-5y,3(y+2)=3-2x4x+8=1-5y4x+5y=-7 (1)3(y+2)=3-2x3y+6=3-2x2x+3y=-3 (2)(2)*2-(1)4x+6y-4x-5y=-6+7y=1x=-3{2/y+3/x=13 (1) 3/y-4/x=3 (2)(1)*4+(2)*38/y+12/x+9/y-12/x=13*4+3*317/y=61y=17/61x=17/33{x+y...

RELATED INFORMATIONS

1. The following equations are solved by the method of addition, subtraction and elimination: (1) x + 1 / 3 = y + 2 / 4, x-3 / 4-y-3 / 3 = 1 / 12, (2) 0.2x + 0.5y = 0.20.4x + 0.1Y = 0.4 The steps of solving the equation must be clear once!
2. The equation (x-1) / X - (8x + a) / 2x (x-1) + X / (x-1) = 0
3. Equation 2x = 14 has the same solution as equation 27-2x = 13______ ．
4. 1 / 7 (2x + 14) = 4-2x solution
5. Equation 6.2x + 14.7 = 89.1
6. (2X-4) / (x + 2x) = 14 / 27 to solve the equation
7. The solution equation (1) x + 4x-3 of 7 has 1 of 7 = 0 (2) 12.4 * 3-2x of 4 = 8
8. Solving equation (6-2x) ^ 2 + x ^ 2 = 8
9. Solving equation 6 (2x-7) = 5 (x + 8) - 12 Another problem is to solve the equation 3x-2 = half x + two thirds
10. Solve the equation, X (8-2x) = 6
11. When m is the value of M, the solutions of 3x-5y = 2m, 2x + 7Y = M-18 are opposite to each other
12. The value of solution X and y of quadratic equation 2x-5y = 7, x-4y = k is also equation x + y = 7, then the value of K is the same
13. X + y = 2009 (1), 3x + 5y-1 + a = 0 (2), 5x + 3Y + 2A = 0 (3) to solve the equation
14. To solve the equation {3 (x-1) + 2 (y + 1) = 8 2 (x-1) - 3Y = 1, it is necessary to find {0.5x-3y = - 1 - 2 / 1 x + 5y-3 = 0
15. It is known that the quadratic equation with one variable x ^ 2-2 (A-1) x - (B + 2) ^ 2 = 0 has real roots. Find the value of a ^ 2001 + B ^ 4
16. -3 = X-9 univariate linear equation
17. The following steps for solving the equation of one variable degree are as follows: 0.2 x-1-0.3 x + 1 = 1, the correct one is A.2 x-1-3 x + 1 = 1, B.2 x-1-3 x + 1 = 1 The following steps for solving the linear equation of one variable 0.2 x-1-0.3 x + 1 = 1 are correct A. 2 / x-1-3 / x + 1 = 1 B. 2 x-1-3 X-1 = 10 10x-10 of c2-10x + 10 of 3 = 1 10x-10 of d2-10x + 10 of 3 = 10
18. To solve the equation: X - | (2 / 3) x + 1 | = 1, use the equation of one variable,
19. It takes 52 hours for one person to finish sorting out a batch of books. Now it is planned that some people will do it for four hours first, and then two more people will work with them for eight hours. Assuming that these people have the same work efficiency, how many people should be assigned to work first?
20. 5.2 solution of linear equation with one variable (1)