function-definition code snippets in matlab

.the first line in the file must define the function using keyword function. the function output must be a variable y, the function name is checkneg and the input must be a variable x in matlab

can i define a function cv = f(t1, t2) and solve for one of its inputs with something like "solve(100 == cv, t1)" in matlab

how to define f in terms of x in matlab in matlab