suatu fungsi f(x)=7-2x terdenfisi pasangan berurutan [(a,5) (b,1) (c,-3)(d,-7) nilai a+B-c+d adalah

jawab

f(x)=  7 - 2x
f(a)= 5
7 - 2a = 5
2a = 2
a= 1

f(b) = 1
7 - 2b= 1
2b = 8
b = 4

f(c)= - 3
7 - 2c = -3
2c =10
c= 5

f(d)= - 7
7 - 2d = -7
2d = 14
d= 7

a+b+c+d = 1 +4 + 5+ 7 
= 17

Persamaan fungsi f(x) = 7 - 2x

(a,5)............ x = a; f(a) = 5
f(a) = 7 - 2a
5 = 7 - 2a
5 - 7 = -2a
-2 = -2a
a = -2 / -2
a = 1

(b,1)............ x = b; f(b) = 1
f(b) = 7 - 2b
1 = 7 - 2b
1 - 7 = -2b
-6 = -2b
b = -6 / -2
b = 3

(c,-3)............ x = c; f(c) = -3
f(c) = 7 - 2c
-3 = 7 - 2c
-3 - 7 = -2c
-10 = -2c
c = -10 / -2
c = 5

(d,-7)............ x = d; f(d) = -7
f(d) = 7 - 2d
-7 = 7 - 2d
-7 - 7 = -2d
-14 = -2d
d = -14 / -2
d = 7

Nilai a + b + c + d adalah
= 1 + 3 + 5 + 7
= 16

Jadi nilai a + b + c + d adalah 16.