Question

7. Calculează, reducând termenii asemenea:
a) (x + 2)(x + 3);
b) (x - 1)(x – 4);
c) (x - 3)(x + 4);
d) (x + 5)(x - 1);
e) (2x + 1)(3x + 2);
f) (4x – 1)(5x + 2);
g) (1 - x)(3x + 1);
h) (4x + 1)(5x – 2)​

Answer 1

Răspuns:

• (a) x² + 5x + 6
• (b) x² - 5x + 5
• (c) x² + x - 12
• (d) x² + 4x - 5
• (e) 6x² + 7x + 2
• (f) 20x² + 3x - 2
• (g) -3x² + 2x + 1
• (h) 20x² - 3x - 2

Explicație pas cu pas:

Salutare!

(a) (x + 2)(x+ 3) =

x² + 3x + 2x + 6 =

x² + 5x + 6

(b) (x - 1)(x – 4) =

x² - 4x - x + 5 =

x² - 5x + 5

(c) (x - 3)(x + 4) =

x²+ 4x - 3x - 12 =

x² + x - 12

(d) (x + 5)(x - 1) =

x² - x + 5x - 5 =

x² + 4x - 5

(e) (2x + 1)(3x + 2) =

6x² + 4x + 3x + 2 =

6x² + 7x + 2

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

20x² + 8x - 5x - 2 =

20x² + 3x - 2

(g) (1 - x)(3x + 1) =

3x + 1 - 3x² - x =

-3x² + 2x + 1

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

20x² - 8x + 5x - 2 =

20x² - 3x - 2

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