1)
3^(5x+12)=81
3^(5x+12)=3^4
5x+12=4
5x=-8
x=-1,6.
2)
(1/5)^(2x-3)=25^(4-3x)
5^(3-2x)=5^(8-6x)
3-2x=8-6x
4x=5
x=1,25.
3)
4ˣ-17*2ˣ+16=0
2²ˣ-17*2ˣ+16=0
2ˣ=t>0
t²-17t+16=0 D=225
t₁=16 2ˣ=16 2ˣ=4⁴ x₁=4
t₂=1 2ˣ=1 x₂=0.
4)
8^(2x²-7x-4)=1
8^(2x²-7x-4)=8^0
2x-7x-4=0 D=81
x₁=4 x₂=-0,5.