Question

log 5+ log (x + 10)-1 = log (21x - 20)-log (2x - 1).
​

Answer 1

Answer:

$log \: 5 + log \: (x + 10) - 1 = log \: (21x - 20) - log \: (2x - 1) \\ log \: 5 + log \: (x + 10) - log \: 10 = log \: (21x - 20) - log \: (2x - 1) \\ log \: 5(x + 10) - log \: 10 = log \: \frac{(21x - 20)}{(2x - 1)} \\ log \: \frac{5(x + 10)}{10} = log \: \frac{(21x - 20)}{(2x - 1)} \: \\ \frac{x + 10}{2} = \frac{21x - 20}{2x - 1} \\ (x + 10)(2x - 1) = 42x - 40 \\ 2 {x}^{2} - x + 20x - 10 = 42x - 40 \\ 2 {x}^{2} - 23x + 30 = 0$

Solve the above equation to find the value of x.

Answer 2

hope it helps you!

answer is - 3/2 or 10