59 2x 3125 136x 3 9x 4Solution154 592x3125 312555555 or

Solution

154)
5^(9-2x)=3125
3125=5*5*5*5*5 or 5⁵
5^(9-2x)=5⁵
now base are same so we can equate their exponents
so,
9-2x=5
adding 2x both sides
9-2x+2x=5+2x
9=5+2x
subtracting 5 from both sides
9-5=5-5+2x
4=2x
dividing both sides by 2
2=x

154)
(1/3)^(6x+3)=9(x-4)
we can write 1/3 as (3^-1)
so we get ,
(3^-1)^(6x+3)=9^(x-4)
9 can be written as 3*3 or 3²
(3^-1)^(6x+3)= 3^2(x-4)
now base are same so we can equare their exponents
-1(6x+3)=2(x-4)
-6x-3=2x-8
adding 6x both sides
6x-6x-3=2x-8+6x
-3=8x-8
adding 8 both sides
8-3=8x-8+8
5=8x
dividing both sides by 8
5/8=x