Question

É urgente, me ajudem por favor :/​

Answer 1

1) (4a - 5b)^2

2) (9x + 3z)^2

3) [ ] (m - n)^2

1) (4a^2+2×4a×(-5b)-5b^2) = (4a+5b)(4a-5b)= (4a-5b)^2

2) (9x^2+2×9x×3z+3z^2) = (9x+3z)(9x+3z)= (9x+3z)^2

3) (m+n)(m-n)= (m-n)^2

4)(x^2 - 18x + 81)=

x^2 - 9x - 9x + 81

x (x - 9) -9 (x - 9)

(x - 9) (x - 9)

(x - 9)^2