Final answer:
To find v in the equation v = u + 10 with u = -21, substitute -21 for u, resulting in a value of v = -11.
Step-by-step explanation:
Given the equation v = u + 10, to find the value of v when u is -21, we simply substitute -21 into the equation for u. The value of t, which is 7 in this case, is irrelevant to the problem since it does not appear anywhere in the given equation.
So, by substituting u = -21 into the equation:
v = -21 + 10 = -11
Thus, the value of v when u= -21 is -11.