Question

Jawablah beserta cara pengerjaannya!

Answer 1

Verified answer

Nomor 7
9^x-1 = 3^1-4x
3^2x-2 = 3^1-4x
2x-2 = 1-4x
6x = 3
x = 3/6 = 1/2

f(y) = y^2 + 2xy + 4x^2
= y^2 + 2.1/2y + 4 (1/2)^2
= y^2 + y + 4.1/4
= y^2 + y + 1

cari nilai minimum menggunakan rumus
f(-b/2a) dari y^2 + y + 1
dengan b = 1 dan a = 1
maka -b/2a = -1/2

f(-b/2a) = (-b/2a)^2 + -b/2a + 1
f(-1/2) = (-1/2)^2 + -1/2 + 1
= 1/4 - 1/2 + 1
= 3/4 (C)


maaf,untuk yang nomor 13 saya cuma bisa
sampai
a^b = 2015^2016 - 2015^2015
= 2015^2015(2015 - 1)
= 2014.2015^2015