2.Suatu fungsi di rumuskan dengan f(x) =6x – 4.Jika f(a) =38,maka nilai a²+2a adalah…
1.Di berikan fungsi : x → x² + 2x.nilai dari f(5) – f(-2) adalah…
No 1.
f(x) = x² + 2x
f(5) – f(-2) =
= f(5)
= 5² + 2(5)
= 25 + 10
= 35
= f(-2)
= -2² + 2(-2)
= -4 + -4
= -8
= f(5) – f(-2)
= 35 -(-8)
= 43
No 2.
f(x) = 6x – 4
f(a) = 38
= (38 + 4)
42 = 6x
42/6 = 7
a = 7
= a² + 2a
= 7² + 2(7)
= 7 x 7 + 2 x 7
= 49 + 14
= 63