f(x)=px+q. f(2)=7. f(4)=11. f(a)=19. f(b)=27. nilai a dan b adalah?

[tex]f(2)=7\Leftrightarrow 2p+q=7[/tex]
[tex]f(4)=11\Leftrightarrow 4p+q=11[/tex]
eliminasi variabel [tex]q[/tex] diperoleh [tex]2p=4\Leftrightarrow p=2[/tex] dan [tex]q=3[/tex]
Dengan demikian diperoleh:
[tex]f(x)=2x+3[/tex]
selanjutnya,
[tex]f(a)=2a+3\Leftrightarrow 19=2a+3\Leftrightarrow a=8[/tex]
[tex]f(b)=2b+3\Leftrightarrow 27=2b+3\Leftrightarrow b=12[/tex]

f(x) = px + q
f(2) = 7 ==» 2p + q = 7.==» q = 7 - 2p
f(4) = 11 ==» 4p + q = 11. subsitusikan q = 7 -2p
4p + (7 -2p) = 11
4p + 7 -2p = 11
2p = 11 - 7
2p = 4
P = 2
q = 7- 2p
= 7 - 2.2
q = 3
Jadi f(x) = 2x + 3
f(a) = 19
2a + 3 = 19
2a = 16
a = 8
f(b) = 27
2b + 3 = 27
2b = 24
b = 12