Question

Suatu fungsi dirumuskan f(x)=ax+b. jika f(-2)=-3 dan f(5)=-10, maka nilai f (-17)adalah?

Answer 1

F(x)=ax+b                                  f(-17)=?
f(-2)=a.-2+b=-3
f(5)=a.5+b=-10
-2a+b=-3
5a+b=-10
b=-3+2a
5a+-3+2a=-10
5a-3+2a=-10
7a=-10+3
7a=-7
a=-1
-2.-1+b=-3
2+b=-3
b=-3-2
b=-5

f(-17)=-1.-17+-5
17-5=12

Answer 2

-2a+b= -3 ......(1)
5a+b=-10 ......(2)
di eliminasi
-7a=7
a=-1
lalu substitusi
-2(-1) +b=-3
2+b=-3
b=-5

f(x)=ax+ b
f(-17)= -1(-17)+(-5)
= 12