1. The problem is to solve the equation $x^2 - t = 0$ for $t$ when $x = -4$. 2. The given equation is $x^2 - t = 0$. We want to isolate $t$. 3. Add $t$ to both sides: $x^2 = t$. 4. Substitute $x = -4$ into the equation: $$(-4)^2 = t$$. 5. Calculate $(-4)^2$: $$16 = t$$. 6. Therefore, the value of $t$ is $16$. This shows that for $x = -4$, $t$ must be $16$ to satisfy the equation $x^2 - t = 0$.