Which expression is equivalent to 2x^2+(4x-6x^2)+9-(6x+3)

-4*(x^2) - 2*x + 6

Step-by-step explanation:

= 2x^2+(4x-6x^2)+9-(6x+3)

= 2*(x^2) + 4*x - 6*(x^2) + 9 - 6*x - 3

= 2*(x^2) - 6*(x^2) + 4*x - 6*x + 9 - 3

= -4*(x^2) - 2*x + 6

an altitude of 15,000 feet

step-by-step explanation:

c. (3,2,6) is the answer.