Answer:
[tex]4x^2-16[/tex]
Step-by-step explanation:
-This is an addition/subtraction problem.
#We subtract the sum of the first two expression from the third expression:
[tex]\#Add \ first \ two\\\\=3x^2 +4x+8 +2x^2-6x+3\\\\=5x^2-2x+11\\\\\# Subtract\ from \ the \ third\\=(9x^2-2x-5)-(5x^2-2x+11)\\\\=9x^2-2x-5-5x^2+2x-11\\\\=4x^2-16[/tex]
Hence, the expression [tex]4x^2-16[/tex] must be added to the first two.
