Given:
an equation is given as below
[tex]-7\cdot20^{x-4}=-49[/tex]
Find:
we have to solve the equation.
Explanation:
Divide both sides of the equation by -7, we get
[tex]20^{x-4}=7[/tex]
Now, by taking log on both sides, we have
[tex]\begin{gathered} log20^{x-4}=log7 \\ (x-4)log20=log7 \\ (x-4)(1.3010)=0.8451 \\ x-4=\frac{0.8451}{1.3010} \\ x-4=0.6496 \\ x=0.6496+4 \\ x=4.6496 \end{gathered}[/tex]
Therefore, the value of x = 4.6496
So, correct option is D, i.e. x = 4.6496
