A) 2x – 7x +3y if x= 3, y= -4
b) y + 3xy if x= 7, y= 5
c) 5x3 + 2y2 if x= 2, y =3

How do you find principle and simple interest

Can some one me with these questions

Worth 100 points need the answers asap first row -x^2 2x^2 (x/2)^2 x^2 x is less than 2 x is greater than 2 x is less than or equal to 2 x is greater than or equal to 2 second row -5 -5/2 4 5 •2 is less than x& x is less than 4 •2 is less than or equal to x & x is less than or equal to 4 •2 is less than or equal to x& x is less than 4 •2 is less than x& x is less than or equal to 4