1) (x+2y) ²

2) 25t² - (2z+3t) ²

3) - c (-d-3) ²

4) 3 (2a+5) ²+5 (2a-3) ²

1) x²+2x+2y + (2y) ²

x²+4xy+4y²

2) (5t - (2z+3t)) • (5t + (2z+3t))

(5t-2z-3t) • (5t+2z+3t)

(2t-2z) • (8t+2z)

2 (t-z) •2 (4t+z)

2•2 (t-z) • (4t+z)

4 (t-z) • (4t+z)

3) - c• (- (d+3)) ²

-c• (d+3) ²

-c• (d²+6d+9)

-cd²-6cd-9c

4) 3 (4a²+20a+25) + 5 (4a²-12a+9)

12a²+60a+75+20 a²-60a+45

32a²+120.