How to do question 5 and 6. Can you explain the first one which is A for 5 and 6?

Thank you

Solve this system of equations. 12x − 18y = 27 4x − 6y = 10

How do i put 3(x+7) in distributive property

The point of intersection of the diagonals of a rectangle is 4 cm further away from the smaller side then from the larger side of the rectangle. the perimeter of the rectangle is equal to 56 cm. find the lengths of the sides of the rectangle. 16 points answer quick