Question

Formule de clacul prescurtat:
(a + b) 2 = a2 + 2 ab+ b2
( a-b)2= a2 – 2ab + b2
(a+b)(a-b)=(a-b)(a+b) = a2 – b2
Exercitii:
( x+3)2=
(4x +5) 2=
(3x +4y)2=
(6a + 4b)2=
( 4y -7 )2=
(2x – 5y) 2=
(x - 4) (x+4) =
( x -5)( x+5) =
( 3 –x) (3+x)=

Ecuatii de gradul I si II:
Exemple:
Gradul I
6x – 30 = 0 | +30
6x = 30 | :6
X = 30 :6
X = 5
2x +7 = 3 | -7
2x = - 4| :2
X= -4: 2
X=-2

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Answer 1

Răspuns:

Explicație pas cu pas:

( x+3)^2=  x^2 + 6x + 9

(4x +5)^2=  16x^2 + 40x + 25

(3x +4y)^2=  9x^2 + 24xy + 16y^2

(6a + 4b)^2=  36a^2 + 48ab + 16b^2

( 4y -7 )^2=  16y^2 - 56y + 49

(2x – 5y)^2=  4x^2 - 20xy + 25

(x - 4) (x+4) =  x^2 - 16

( x -5)( x+5) =  x^2 - 25

( 3 –x) (3+x)= 9 - x^2