Arectangle is cut in half along the diagonal to form a triangle. if the area of the triangle is (2x + 10) cm^2, what is the area of the rectangle? provide steps and reason for your answer too!

Since it's literally cut in half, that means the triangle's area is literally half of the rectangle's area. Therefore, if we write it as
the triangle's area (a)=(1/2)*(b) (the rectangle's area) we can multiply 2 to both sides to get 2*a=b. Since a is (2x+10), we can plug it in and use the distributive property (since we just can't add up variables and integers) to get 
2*(2x+10)=4x+20=b