So we are given the formula:
[tex] \frac{1}{[NO_{2}]}= \frac{kt+1}{[NO_{2}]_{0}} [/tex]
Then we multiply [tex] [NO_{2}]_{0} [/tex] on both sides to cancel out the right side, and bring it to the numerator on the left side:
[tex] \frac{[NO_{2}]_{0}}{[NO_{2}]} =kt+1 [/tex]
And now we multiply [tex] [NO_{2}] [/tex] to both sides to cancel out the left side, and bring it to the numerator essentially on the right side:
[tex] [NO_{2}]_{0}=(kt+1)[NO_{2}] [/tex]
And now we have the equation solved for [tex] [NO_{2}]_{0} [/tex].