jika A=2×+1 B=2-× c=×+5 maka sederhanaka bentuk aljabar berikut A. a^2-b^2-c^2 B.a^2+b^2+c^2 C.b^2-ac D.C^2+ab E.2a+2b-2c tolong di jawab ya

diketahui :
a = 2x + 1
b = 2 - x
c = x + 5

penyelesaian
A) a² - b² - c²
= (2x + 1)² - (2 - x)² - (x + 5)²
= 4x² + 4x + 1 - 4 + 4x - x² - x² - 10x - 25
= 2x² - 2x - 28

B) a² + b² + c²
= (2x + 1)² + (2 - x)² + (x + 5)²
= 4x² + 4x + 1 + 4 - 2x + x² + x² + 10x + 25
= 6x² + 12x + 30 

C) b² - ac
= (2 - x)² - [(2x + 1) (x + 5)]
= 4 - 4x + x² - 2x² - 10x - x - 5
= -x² - 15x - 1

D) c² + ab
= (x + 5)² + [(2x + 1) (2 - x)]
= x² + 10x + 25 + 4x - 2x² + 2 - x
= -x² + 13x + 27

E) 2a + 2b - 2c
= 2(2x + 1) + 2(2 - x) - 2(x + 5)
= 4x + 2 + 4 - 2x - 2x - 10
= -4

a. a^2 - b^2 -c^2
=( 2x+1)^2 - (2-x)^2 - (x+5)^2
=( 4x^2 +4x +1) - (4 -4x +x^2) - (x^2 + 10x + 25)
= 4x^2 - x^2 - x^2 + 4x +4x -10x +1 -4 -25
= 2x^2 -2x -28

b. a^2 + b^2 + c^2
= (2x+1)^2 +(2-x)^2 +(x+5)^2
= (4x^2+4x+1) + (4-4x+x^2) +(x^2 +10x + 25)
,= 4x^2 + x^2 +x^2 + 4x -4x +10x +1+4+25
= 6x^2 +10x +30

c. b^2 - ac
= (2-x)^2 - (2x+1)(x+5)
=( 4 -4x+x^2) - ( 2x^2 +11x +5)
= x^2 - 2x^2 -4x -11x +4 -5
= -x^2 -15x -1

d. c^2 + ab
= (x+5)^2 + (2x+1)(2-x)
= (x^2 +10x+25) + (4x -2x^2+2 -x)
= ( x^2+10x+25) + (-2x^2 +3x +2)
= x^2-2x^2 +10x +3x +25+2
= -x^2 +13x+27

e. 2a + 2b - 2c
= 2(2x+1) +2(2-x) -2(x+5)
= 4x +2 + 4 - 2x - 2x - 10
= 4x -4x +2+4-10
= -4
maaf jika salah