Question

5^(2x-1)+5^(x+1)=250 how do you solve? thank you

Answer 1

Answer:

x = 2

Step-by-step explanation:

Exponential Equations

Solve:

$5^{2x-1}+5^{x+1}=250$

Separate each exponential:

$5^{2x}5^{-1}+5^{x}5^{1}=250$

Operating:

$\displaystyle \frac{5^{2x}}{5}+5^{x}5=250$

Multiplying by 5:

$5^{2x}+25\cdot5^x=1250$

Rearranging:

$5^{2x}+25\cdot5^x-1250=0$

Recall that:

$5^{2x}=(5^{x})^2$

$(5^{x})^2+25\cdot5^x-1250=0$

Calling

$y=5^{x}:$

$y^2+25y-1250=0$

Factoring:

$(y-25)(y+50)=0$

There are two possible solutions:

y=25

y=-50

Since

$y=5^{x}$

y cannot be negative, thus:

$5^{x}=25=5^2$

The solution is:

x = 2