Type the correct answer in each box. Consider the expressions shown below.
A -7x^2-2x+5
B 7x^2-2x+7
C 7x^2+2x-5
Complete the following statements with the letter that represents the expression.
(3x^2-6x+11)-(10x^-4x+6) is equivalent to expression___ .
(-3x^2-5x-3)-(-10x^2-7x+2) is equivalent to expression___ .
(12x^2+6x-5)-(5x^2+8x-12) is equivalent to expression ___ .