Hey there! I'm happy to help!
NUMBER 1
This is a trick to solve any proportion.
Multiply the diagonal numbers.
5(16)=80
Divide by the number that isn't the one you want to find.
90/8=10
And you are left with the number you haven't touched. We haven't touched x, so x=10.
NUMBER 2
Cross multiply.
45(-50)=-2250
Divide.
-2250/3=-750
So x=-750.
QUESTION 3
4(27)=108
108/12=9
So x+3=9, subtract 3 from both sides x=6.
Have a wonderful day! :D
