Question

1.Calculati:
(x+2)²
(x-9)²
(1/2-1)²
(3x-7)(3x-7)
(x+2)²+(x-3)²-(x+4)(x-4)
sa se faca cu cele 2formule calcul prescurtat:
(a+b)²=a²+2ab+b²
(a- b)²=a²-2ab+b²

Answer 1

${(x + 2)}^{2} = {x}^{2} + 4x + 4$

${(x - 9)}^{2} = {x}^{2} - 18x + 81$

${( \frac{1}{2} - 1) }^{2} = \frac{1}{4} - 1 + 1 = \frac{1}{4}$

$(3x - 7)(3x - 7) = {(3x - 7)}^{2} = 9{x}^{2} - 42x + 49$

${(x + 2)}^{2} + {(x - 3)}^{2} - (x + 4)(x - 4)$

$= {x}^{2} + 4x + 4 + {x}^{2} - 6x + 9 - {x}^{2} + 4$

$= {x}^{2} - 2x + 17$