Question

Nomor 3 buat caranya ya

Answer 1

Xlog 4 + 2log x = 3
xlog 2^2 + 2log x = 3
2 . xlog 2 + 2log x = 3
2 . 1/(2log x) + 2log x = 3 (kali 2log x kedua ruas)
2 + 2log^2 x = 3log x
2log^2 x - 3 . 2log x + 2 = 0
misalkan 2log x = y
y^2 - 3y + 2 = 0
y^2 - 2y - y + 2 = 0
y(y - 2) - 1(y - 2) = 0
(y - 1)(y - 2) = 0
y = 1 atau y = 2

Jika y = 1:
2log x = 1
2^1 = x
x = 2

Jika y = 2:
2log x = 2
2^2 = x
x = 4

a = 2
b = 4

a + b = 2 + 4 = 6

Jawaban: E

Answer 2

Misal x'log 4 = y--> 4'log x = 1/y  --> x = 4^(1/y)
1/2. 2'log x = 1/y
2'log y = 2/a

x'log 4 + 2'log x = 3
y + 2/y = 3
y²- 3y + 2 = 0
(y - 2)(y -1)= 0
y= 2 atau y = 1

y= 2 --> a = 4^(1/2) = 2
y= 1 --> b= 4^(1) = 4

a+ b = 2+4= 6