The equation is:
[tex]-1\text{ = -}\frac{4}{7}\text{ t}[/tex]To find t you need to isolate t.
First, pass the 7 multiplying and the 4 dividing:
[tex]-1\cdot\frac{7}{4}=-t[/tex]Finally, pass the minus sign:
[tex]-t\text{ = (-1)}\cdot t=-1.\frac{7}{4}\Rightarrow\text{ t = (-1)}\cdot\frac{7}{4}\frac{1}{(-1)}=\frac{7}{4}[/tex]