Answer:
8x²-25x+7......
Explanation:
A² = (3x-4)(3x-4)
A² = 3x(3x-4) - 4(3x-4)
A² = 9x² - 12x - 12x + 16
A² = 9x² - 24x + 16
while
B+C = (x+7) + (x² +2)
B+C = x+7+x²+2
B+C = x²+x+9
Therefore:
A² - (B+C) = 9x² - 24x + 16 - (x²+x+9)
= 9x² - 24x + 16 - x² - x - 9
= 8x²-25x+7