Question

If z(t) = 2t2 + 7t – 4, find z(–2) and z(7).

A. z(–2) = 11; z(7) = 101
B. z(–2) = –26; z(7) = 143
C. z(–2) = –2; z(7) = 241
D. z(–2) = –10; z(7) = 143

Answer 1

$z(t)=2t^2+7t-4\\\\z(-2)\to\text{substitute t=-2 to the equation}\\\\z(-2)=2(-2)^2+7(-2)-4=2(4)-14-4=8-14-4=-10\\\\z(7)\to\text{substitute t=7 to the equation}\\\\z(7)=2(7^2)+7(7)-4=2(49)+49-4=98+49-4=143$

Answer: D. z(-2) = -10; z(7) = 143