Answer:
81x² + 90x + 48y + 64
Step-by-step explanation:
(9x+8)² = (9x+8)(9x+8) = 9x*9x + 9x*8 + 8*9x + 8*8 = 81x² + 72x + 72x + 64
= 81x² + 144x + 64
then:
(9x+8)² -54x+48y = (81x² + 144x + 64) -54x + 48y = 81x² + 90x + 48y + 64
