jika x dan y adalah penyelesaian dari sistem persamaan 2x + 7y = 11 dan 5x + 3y = 13. nilai x + y =...

2x + 7y = 11   (x5)
5x + 3y = 13   (x2)
-------------------------
10x + 35y = 55
10x + 6y = 26
------------------------ -
29y = 29
y = 1

2x + 7y = 11
2x + 7(1) = 11
2x + 7 = 11
2x = 11 - 7
2x = 4
x = 2

maka
x + y = 2 + 1 = 3

• Cari nilai y

2x + 7y = 11 ...×5
5x + 3y = 13 ... ×2
—————————
10x + 35y = 55
10x + 6y = 26
———————— —
29y = 29
y = 29/29 = 1

• Cari nilai x

2x + 7y = 11
2x +7(1) = 11
2x + 7 = 11
2x = 11 - 7
2x = 4
x = 4/2 = 2

• Cari nilai x+y

x = 2
y = 1

Maka, x + y = 2 + 1 = 3 ⬅ jawaban