When P(x)=3x^ 2+2y-6 and Q(x)=x^2-6y+7 find
a)P(x)-Q(x)
b)2P(x)+Q(x)
c)3P(x)-2Q(x)
a) P(x) - Q(x) = (3x^2 + 2y - 6) - (x^2 - 6y + 7)
= 3x^2 + 2y - 6 - x^2 + 6y - 7
= (3x^2 - x^2) + (2y + 6y) - (6 + 7)
= 2x^2 + 8y - 13
b) 2P(x) + Q(x) = 2(3x^2 + 2y - 6) + (x^2 - 6y + 7)
= 6x^2 + 4y - 12 + x^2 - 6y + 7
= (6x^2 + x^2) + (4y - 6y) + (-12 + 7)
= 7x^2 - 2y - 5
c) 3P(x) - 2Q(x) = 3(3x^2 + 2y - 6) - 2(x^2 - 6y + 7)
= 9x^2 + 6y - 18 - 2x^2 + 12y - 14
= (9x^2 - 2x^2) + (6y + 12y) - (18 + 14)
= 7x^2 + 18y - 32