<span>Using the information we have
3x+4=40
Do the same to each side of the equation to eliminate for x.
3x+4=40 Minus 4 from each side
3x=40-4
3x=36
Divide 3 from each side
x=36/3
x=12
AC=3x+4
insert the value of x
3(12)+4=40
AC=40
AD=20</span>
The value of a is -6
The value of b is 48
= 12*5 + 12*3i - 5*2i - 6i^2 (remember that i^2 = -1) so:-
= 60 +26i - 6*(-1)
= 60 + 26i + 6
= 66 + 26i