Question

ДАЮ ВСЕ 45 БАЛОВ ПОМОГИТЕ СРОЧНО НАДО!!!!!!!!!!!!

Answer 1

4)

$(2x - 5) {}^{2} + 5( {x}^{2} + 10x) = (3x + 5) { }^{2} \\ 4 {x}^{2} - 20x + 25 + 5 {x}^{2} + 50x = (3x + 5) { }^{2} \\ 9 {x}^{2} + 30x + 25 = (3x + 5) {}^{2} \\ (3x) {}^{2} + 2 \times 3x \times 5 + {5}^{2} = (3x + 5) {}^{2} \\ (3x + 5) {}^{2} = (3 {x + 5)}^{2}$

5)

а) 61² = (60+1)² = 60² + 2×60×1 + 1² = 3 600 + 120 + 1 = 3 721

б) 199² = (200-1)² = 200² - 2×200×1 + 1² = 40 000 - 400 + 1 = 39 600 + 1 = 39 601