Step-by-step explanation:
[tex] {e}^{7x} = 90 \\ taking \: log \: both \: sides \\ log \: {e}^{7x} = log\: 90 \\ \\ \therefore \:7x \: log \: {e}= log\: 90\\ \\ \therefore \:7x \: \times 1= log\: 90..( \because \: log \: {e}= 1) \\ \\ \therefore \:7x = 1.95424250944 \\ \\ \therefore \:7x =1.95 \\ \\ \therefore \:x = \frac{1.95}{7} \\ \\ \therefore \:x =0.27857142857 \\ \\ \therefore \:x =0.2786[/tex]
