Answer:
13x^2 -7x -6
Explanation:
(9x^2-7x) - (-4x^2+6)
after organizing subtracting these will be difficult so we will switch
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(9x^2-7x) + (4x^2-6)
remember that the numbers after the subtract sign either be negative to positive or vis versa
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adding it as normal
9x^2+4x^2
-7x+0
0+(-6)
13x^2 -7x -6
ax^2 -bx +c