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**Opalg** You need to put the given information into both those formulas.

For the formula $\displaystyle v(t)= v_0 + at$, you have $\displaystyle v(t) = 88$ and $\displaystyle v_0 = 132$, which tells you that $\displaystyle at = -44$ (it's negative because the car is decelerating, so $\displaystyle a$ is negative).

For the formula $\displaystyle s(t) = s_0 + v_0t + \tfrac12at^2$, you have $\displaystyle s(t) = 200$, $\displaystyle s_0=0$ and $\displaystyle v_0=132$. Plug those into the formula and you get $\displaystyle 200 = 132t + \tfrac12(at)t$. I have written the last term $\displaystyle \tfrac12at^2$ as $\displaystyle \tfrac12(at)t$, because you can now substitute in the value for $\displaystyle at$ that you got from the previous equation. You then have a simple equation for $\displaystyle t$, and once you know $\displaystyle t$ you can put it into the formula $\displaystyle at = -44$ to find $\displaystyle a$.