yang no 15,16,18 apa jawabannya

15]
7^(x^2) = 49^(2x^2 - 3x)
7^(x^2) = (7^2)^(2x^2 - 3x)
7^(x^2) = 7^(2×(2x^2 - 3x))
7^(x^2) = 7^(4x^2 - 6x)
x^2 = 4x^2 - 6x
4x^2 - x^2 - 6x = 0
3x^2 - 6x = 0
3x(x - 2) = 0
3x = 0 atau x - 2 = 0
x = 0/3 atau x = 2
x = 0

HPnya = {0 dan 2} (c)

16]
2^(x^2 + 3x - 1) < 2^(x^2 - 2x + 4)
x^2 + 3x - 1 < x^2 - 2x + 4
x^2 + 3x - x^2 + 2x < 4 + 1
5x < 5
x < 5/5
x < 1

HPnya = {x < 1} (d)

18]
9^x - 3^(x + 1) - 54 > 0
(3^2)^x - (3^x . 3) - 54 > 0
3^2x - (3 . 3^x) - 54 > 0

Misal : a = 3^x
a^2 - 3a - 54 > 0
(a - 9)(a + 6) > 0
a - 9 > 0 atau a + 6 > 0
a > 9 atau a > -6

a = 3^x
a > 9
3^x > 3^2
x > 2

a > -6
3^x > -6
(Tidak memenuhi)

HPnya = {x|x > 2} (d)