you must substitute x in the equation given :)
examples:
when x is -2
therefore, y = 2(-2) + 3
y = -1
when x is 0
therefore, y = 2(0) + 3
y = 3
when x is 1
therefore, y = 2(1) + 3
y = 5
when x is 3
therefore, y = 2(3) + 3
y = 9
for (b) you only have to plot based on the table ;)
hope this helps
Differentiate the given solution:

Substitute
and
into the ODE:

and it's easy to see the left side indeed reduces to 0.
There is no square root of five...
X=⁻3 and x=1
because
a+b=2 which means a=3 and b=⁻1 which added up equals 2
a×b=⁻22 which means that 11 which is a×⁻2 which is b=⁻22