help svp pour demain

exercice 1
2(3x+1) +3(7-2x)
6x+2+21-6x
=23
(2x-1)² -(3x²+1)
4x²-4x+1 -3x²-1
x²-4x

exercice 2

25x²+20x+4
(5x+2)²

x²-4
=(x-2)(x+2)

exercice 3

2x+3 = -2
2x = -2-3
2x =-5
x =  -5/2


10-3x= 5x+6
-3x-5x = 6 -10
-8x = -4
x = -4/-8
x = 1/2

exercice 4

a =(2x+1)(4x-7) -(2x+1)²
a =8x²-14x+4x-7 -(4x²+4x+1)
a = 8x²-10x-7 -4x²-4x-1
a = 4x²-14x-8


factoriser

a =(2x+1)(4x-7) -(2x+1)²
a =(2x+1)(4x-7-2x-1)
a =(2x+1)(2x-8)
a = 2(2x+1)(x-4)


resoudre l equation

(2x+1)(2x-8) = 0

2x+1 =0                          2x-8 =0
2x = -1                              2x =8
x =  -1/2                                x = 8/2 = 4

donc solution  -1/2  et 4