The measure of the supplement of angle A...
That's 180°-A
So far we have -->                    180°-A
...is...
That's equal =
So far we have -->                     180°-A =
...40 degrees larger than... 
that means that we are to add 40° onto what's after "than"
So far we have -->                     180°-A =          +40°  
(skipping a space for what's after "than"): 
...twice... 
That means that what's after "than" starts with 2× (*two times") 
So far we have -->                     180°-A = 2×       +40°
...the measure of the complement of angle A...
That's (90°-A), so that's what we put after the 2× and before
the +40°
Now we have the finished equation: 
                                       180°-A = 2×(90°-A)+40°
So we solve it
Distribute the 2×
                                       180°-A = 2×90°-2×A+40°
Multiply 2×90° get 180°
                                       180°-A = 180°-2A+40°
Subtract 180° from both sides:
                                           -A = -2A+40°
Add 2A to both sides
                                            A = 40°
...What is the sum in degree of the measures of the supplement... 
That's 180°-A
       180°-40°
       140°
...and complement of angle A?...
That's 90°-A
       90°-40°
       50°
Edwin