Question

5x+2y=-3. x+5y=4. solve by elemination method​

Answer 1

Step-by-step explanation:

(i) 5x + 2y = -3 …(i) x + 5y = 4 ∴ x = 4 – 5y …(ii) Substituting x = 4 – 5y in equation (i), we get 5(4 – 5y) + 2y = -3 ∴ 20 – 25y + 2y = -3 ∴ -23y = -3 – 20 ∴ -23y = -23 ∴ y =−23−23−23−23 = 1 Substituting y = 1 in equation (ii), we get x = 4 – 5(1) = 4 – 5 = -1 ∴ (x, y) = (-1, 1) is the solution of the given simultaneous equations. Substituting y = 3 in equation (i), we get x = 10 – 3(3) = 10 – 9 = 1 ∴ (x, y) = (1, 3) is the solution of the given simultaneous equations. .(iii) 99x + 101 y = 499 …(i) 101 x + 99y = 501 …(ii) Adding equations (i) and (ii), we get 99x + 101y = 499 Substituting x = 3 in equation (iii), we get 3 + y = 5 ∴ y = 5 – 3 = 2 ∴ (x, y) = (3, 2) is the solution of the given simultaneous equations. iv. 49x – 57y = 172 …(i) 57x – 49y = 252 …(ii) Adding equations (i) and (ii), we get 49x – 57y = 172 Substituting x = 7 in equation (iv), we get 7 + y = 10 ∴ y = 10 – 7 = 3 ∴ (x, y) = (7, 3) is the solution of the given simultaneous equationsRead more on Sarthaks.com - https://www.sarthaks.com/841214/solve-the-following-simultaneous-equations-i-5x-2y-3-x-5y-4?show=841348#a841348

Answer 2

Answer:

x = -1 and y = 1

Step-by-step explanation:

5x+2y=-3        (1)

x+5y=4     (2)

Multiply (2) by 5

∴ 5x+25y=20    (3)

Subtract (3) from (1)

∴    5x+25y=20

-     5x+2y = -3

___-__-___+__

          23y = 23

              y = 23/23

             y = 1

Substitute y = 1 in (2)

x + 5y = 4

∴x + 5(1) = 4

∴x + 5 = 4

∴      x = 4 - 5

∴      x = -1