add maths topic integration urgent

[TMK]

1.The rate of change of a quantity L with respect to t is given by dL/dt=3t-2. If L=3 when t=2, find the value of L when t=4.

2. A quantity u varies with respect to t so that du/dt=a+bt where a and b are constant. Given that it has a minimum value of 11/2 when t=1 and that its rate of change when t=2 is -3, find u in terms of t.

Plz can u work out these questions for me!!
these r add maths questions on chapter integration

i need it 2day before 3.00p.m plzz urgent

[MathTutor]

L= int(3t-2) dt
L= 1.5t^2-2t+c
when t=2 , L=3
c=1
L=1.5t^2-2t+1
When t=4, L= 17

when t=1, du/dt=a+b=0 ........eq1
when t=2, du/dt=a+2b=-3 .......eq2
solve eq1 and eq2 we get a=3, b=-3
du/dt=3-3t
integrate w.r.t t
u=3t-1.5t^2+c
when t=1 u=5.5
c=4
u=3t-1.5t^2+4

d^2u/dt^2=b=-3<0
It is not minimum but a maximum