The two problems are almost identical: you have to set up a system, and then solve it.
In the first case, let 
and 
be, respectively, the number of girls and boys.
We know that 
(the number of girls in the Spanish Club is four more than twice the number of boys). Also, we know that 
(there are 61 students in total).
So, we have the system
We can use the first equation to substitute in the second
And then solve for :
For the second problem, let 
and 
be the number of pins knocked down by, respectively, Carrie and John. Just like before, we have the system
And you can solve it in the very same way we solved the previous one.
Measure of the flour is greater than the measure of the sugar
First, you gotta simplify. There’s really nothing to simplify so just take it out of the parenthesis.
2x-8=2x-4
Now turn the -8 into a +8. Add it on each side.
2x=2x+8
Now turn the 2x on the right into a negative. Do the same thing you did with the 8.
Now it’s:
0 = 8
That means there’s no solution.
Hope this helped :)
