Answer:
a. x = 12
b. 12 years after 1970, the number of men graduating equals the number of women graduating.
c.
Step-by-step explanation:
We have the system

and we solve it by substituting the value of y from the first equation into the second equation:

subtracting 314 from both sides gives

subtracting 3.7 from both sides gives

Finally, dividing both sides by 127 gives


which rounded to the nearest whole number is

The solution tells us that 12 years after 1970, the number of men graduating equals the number of women graduating.
The graph of the equations is given below:
By looking at the slope we see that more women graduate than men and after 12 years, the number of graduating women is greater than men.