The second one. There is a side, an angle, and another side.
Y=3
to solve this you just substitute 4 in for x into the equation and solve for y. since negative 3 plus 7 is 4, y=4
B is your answer.
Because 7 times 8 is 56 and 7 times 3 is 21.
The answer will be calculated by Pythagoras theorem here -
Try subtracting first there were 10 then four were sold I don't know what happens after but thats what I know