-9+2
(25/4)^-1/2
x + y + z = 6 x + 2z = 7 3x + y + z = 12 solve using inverse
9+-12
9--12
one number is one more than twice the other number
8--12
From first principle differentiate y=x square +x+1
9+-5
(1+x)**(3/2)