Diketahui suatu fungsi f(x) = ax + b, jika f(1) = 3 dan f(3) = 13, maka nilai a + b adalah....

fungsi f(x) = ax + b
f(1) = 3
f(3) = 13

Ditanya a + b

Jawaban:
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f(1)........ = 3
ax + b.. = 3
a(1) + b = 3
a + b.....= 3
...... b.... = 3 - a........... (1)

f(3)........ = 13
ax + b... = 13
3a + b... = 13............(2)


Subtitusi nilai b

3a + b = 13
3a + (3 - a) = 13
3a - a......... = 13 - 3
2a............... = 10
a................. = 10/2
a...................= 5


Nilai b :
= 3 - a
= 3 - 5
= -2


Sehingga, nilai a + b :
= a + b
= 5 + (-2)
= 5 - 2
= 3 ✔

jadi, nilai a adalah 5
nilai b adalah -2
jadi nilai a+b = 3