First you subtract 47 from both sides (-47 from 47 and -47 from 32)
Then you get -3x = -15
Divide -3 from -3x and -3 from -15
Leaving you with X = 5
(9x^2+8x)-(2x^2+3x)
9x^2+8x-2x^2-3x
7x^2+5x
Are you asking for definition because if so i believe what you’re looking for is absolute value