Diketahui f(x) = 2x - 3, pada himpunan bilangan bulat dinyatakan dalam pasangan berurutan {(a,3), (b,-5), (-2,c), (-1,d)}. Nilai a + b + c - d adalah....

f(x) = 2x - 3

(a, 3), berarti f(a) = 3
f(x) = 2x - 3
f(a) = 2a - 3
3 = 2a - 3
2a = 3 + 3
2a = 6
a = 6 : 2
a = 3

(b, -5), berarti f(b) = -5
f(x) = 2x - 3
f(b) = 2b - 3
-5 = 2b - 3
2b = -5 + 3
2b = -2
b = -2 : 2
b = -1

(-2, c), berarti f(-2) = c
f(x) = 2x - 3
f(-2) = 2(-2) - 3
c = 2(-2) - 3
c = -4 - 3
c = -7

(-1, d), berarti f(-1) = d
f(x) = 2x - 3
f(-1) = 2 (-1) - 3
d = 2 (-1) - 3
d = -2 - 3
d = -5

Maka, a + b + c - d = 3 + (-1) + (-7) - (-5) = 3 - 1 - 7 + 5 = 0