Question

Diketahui f(x)=ax+b,jika f(3)=8 dan f(-2)=-7,maka nilai a-b adalah

Answer 1

F(3) ~> a(3) + b = 8
3a + b = 8... Persamaan 1
f(-2) ~> a(-2) + b = -7
-2a + b = -7.. Persamaan 2

3a + b = 8
-2a + b = -7  -
5a = 15
a = 3

3a + b = 8
3(3) + b = 8
9 + b = 8
b = 8 - 9
b = -1

Maka, nilai a - b = 3 - (-1)
= 3 + 1
= 4

Answer 2

F(x)=ax+b
f(3)=8
f(-2)=-7

f(x)=ax+b
f(3)=a.3+b
8=3a+b

f(x)=ax+b
f(-2)=a.(-2)+b
-7=-2a+b

3a+b=8
-2a+b=-7
_________-
5a=15
a=3

3a+b=8
3.3+b=8
9+b=8
b=-1

jadi, a-b=3-(-1)=3+1=4