Diketahui system persamaan 2×+5y=-13 dan ×-3y=10 Nilai ×+y adalah

2x + 5y = -13 dikali 1
x- 3y = 10 dikali 2

2x + 5y = -13
2x - 6y = 20
------------------ -
11 y = -33
y = -3

× - 3y = 10
x -3 (-3) = 10
x + 9 = 10
× = 1

2x + 5y = -13 dikali 1
x - 3y = 10 dikali 2

2x + 5y = -13
2x - 6y = 20
------------------ --
11y = -33
y = -33/11
y = -3

y = -3 disubtitusikan ke 2x + 5y = -13
2x + 5y = -13
2x + 5 (-3) = -13
2x - 15 = -13
2x = -13 + 15
2x = 2
x = 2/2
x = 1

Nilai x + y
= 1 + (-3)
= 1 - 3
= -2


Moga membantu...