So I am trying to prepare for a final in a few hours and i am working with three old final keys provided for us to study with, and I am super stuck on something I think is probably super obvious........SO number 3... i totally understand where the integrated portions of the acceleration vector came from, but for the LIFE of me i cannot figure out where the addition and subtraction in the parentheses is coming from. like why is it +3 in i? why no arithmetic in j? why -3 in k?? I have three practice exams to work with and none show any specific work for this problem and idk how to dig myself out of this without help because like i said, every example i look at i understand everything except why there's random addition and subtraction in the vector coefficient things. can someone help? I couldn't add multiple pics but i did my best to make sure all three example problems were visible. none show work or explain where these operations came from and frankly this final is in 5 hours and I really need help because there are MUCH harder concepts i need to be practicing haha.

3. The acceleration vector of a particle is given by a()=60/"i+21/j+50t' k. v(1)=8i+3j+2 k, find the velocity vector at any time t. (10 points)~ rie =( 5 *12+ 3] 23 + (326 ) = +( 5710- 3 )k W- CJ 3. The acceleration vector of a particle is given by a(/)=4471i+201j-18/ k. If .v(1)=51+6j-+9 k, find the velocity vector at any time t. (10 points) YO = (4. 1 + ( 10* - 4 ) + ( 6+ / 3). TV 220 3. The acceleration vector of a particle is given by a(t)=18 i+6tj+287 k. If v(1)=4i+5j+3 k, find the velocity vector at any time t. (10 points) VITT = ( 3 ( + 1 ) 2 + ( 32 2 + 2] , + ( 7+ 4- 4 ).K