Answer:
option C is correct.
Step-by-step explanation:
Checking equation A
[tex](9x^3 + 12x) + (16x^3 -4x+1)= 24x^3 +16x-1\\9x^3+16x^3+12x-4x+1=24x^3+16x-1\\25x^3+8x+1\neq 24x^3+16x-1[/tex]
Checking equation B
[tex](3x+2x^2-4)-(x^2+x-5)=2x+x^2-9\\3x-x+2x^2-x^2-4+5=2x+x^2-9\\2x+x^2+1\neq 2x+x^2-9[/tex]
Checking equation C
[tex](10x^3+2x^2-11)+(9x^2+2x-2)=10x^3+11x^2+2x-13\\10x^3+2x^2+9x^2+2x-11-2=10x^3+11x^2+2x-13\\10x^3+11x^2+2x-13=10x^3+11x^2+2x-13[/tex]
Checking equation D
[tex](-7x^2+12)-(5-4x^2)=11x^2-17\\-7x^2+4x^2+12-5=11x^2-17\\-3x^2+7\neq 11x^2-17[/tex]
Hence, only option C is correct.
