Question

a) (5-2x)²-(x-2)(x+4)+3(x-2)²+3
b) (2x-1)²-4(x+½)²= -(3,6+6x)

Tylko prosze te przykłady po kolei rozpisać ;)

Answer 1

a) (5-2x)²-(x-2)(x+4)+3(x-2)²+3= 25-20x+4x²-x²-4x+2x+8+3(x²-4x+4)+3= 3x²-22x+33+3x²-12x+12+3= 6x²-34x+48

 

b) (2x-1)²-4(x+½)²= -(3,6+6x)

4x²-4x+1-4(x²+x+1/4)=-3,6-6x

4x²-4x+1-4x²-4x-1+3,6+6x=0

-2x=-3,6   /:(-2)

x=1,8

 

Answer 2

a) (5-2x)²-(x-2)(x+4)+3(x-2)²+3 =

= 5² - 2 · 5 · 2x + (2x)² - (x·x + x·4 - 2·x - 2·4) + 3(x² - 2·x·2 + 2²) + 3 =

= 25 - 20x + 4x² - (x² + 4x - 2x - 8) + 3(x² - 4x + 4) +3 =

= 28 - 20x+ 4x²- x²- 4x+ 2x+ 8+ 3x² - 3·4x + 3·4 =

= 36 + 6x² - 22x - 12x+ 12 =

= 6x² - 34x + 48

b) (2x-1)²-4(x+½)²= -(3,6+6x)

(2x)² - 2 · 2x · 1 + 1² - 4(x² + 2 · x · ½ + (½)² ) = -3,6 - 6x

4x² - 4x + 1 - 4(x² + x + ¼) = -3,6 - 6x

4x²- 4x + 1 - 4x²- 4x - 1 = -3,6 - 6x

-8x = -3,6 - 6x

-8x + 6x = -3,6

-2x = -3,6  |:(-2)

x = 1,8