Question

(x+1)(x-2)-(x+5)(x+4)=-2


(a+3)(a-b)+(9-5a)(a+1) если a =1 1/4

Answer 1

$(x + 1)(x - 2) - (x + 5)(x + 4) = {x}^{2} - 2 x + x - 2 - {x}^{2} - 4x - 5x - 20 = - 10x - 22$


$(a + 3)(a - b) + (9 - 5a)(a + 1) = (1 frac{1}{4} + 3)(1 frac{1}{4} - b) + (9 - 5 times 1 frac{1}{4} )(1 frac{1}{4} + 1) = 4 frac{1}{4} times 1 frac{1}{4} - 4 frac{1}{4} b + (9 - frac{5 times 5}{4} ) times 2 frac{1}{4} = frac{17 times 5}{16} - 4 frac{1}{4} b + (9 - 6 frac{1}{4} ) times frac{9}{4} = frac{85}{16} - 4 frac{1}{4} b + 2 frac{3}{4} times frac{9}{4} = 5 frac{5}{16} - 4 frac{1}{4} b + frac{11 times 9}{16} = 5 frac{5}{16} - 4 frac{1}{4} b + 6frac{3}{16} = 11 frac{8}{16} - 4 frac{1}{4} b = 11.5 - 4.25b$