Question

02). Penyelesaian system persamaan dari:
2x + 3y = 19 dan x - y = -8 adalah ((x,y)). Nilai x - 7y = ...
tolong dengan cara.

Answer 1

X - y = -8 ---> x = y - 8
2x + 3y = 19
2(y-8) + 3y = 19
2y - 16 + 3y = 19
2y + 3y = 19 + 16
5y = 35
y = 35/5
y = 7

x = y - 8
x = 7 - 8
x = -1

Hp = (-1,7)

maka nilai x - 7y = -1 - 7(7) = -1 -49 = -50

Answer 2

2x + 3y = 19 dikali 1 2x + 3y = 19
x - y = -8      dikali 2 2x - 2y = -16 -
                                     5y = 35
                                       y = 7
x - y = -8
x - 7 = -8
x = -8 +7
x = -1
jadi, nilai x - 7y = -1 - 7.7 = -1 -49 = -50