\(A=\left(x+7\right)^2-\left(x-7\right)^2\)
\(=x^2+14x+49-x^2+14x-49\)
\(=28x\)
Vậy A = 28x
A=(x+7)2-(x-7)2
<=> A=(x+7+x-7)(x+7-x+7)
<=> A= 2x . 14 = 28x
A, (x-2)^2=4x^2+4x+1 B, 25x^2-9=0 C, (2x-1)^2+(x+3)^2-5(x+7)(x-7)=0 D, (2x+1)(x-4)-2(x-3)^2=8 E, (3x-1)^2=(5-x)^2
Bài 1Tìm x
a,(x+4)^2-(x+1)(x-1)=16
b,(2x-1)^2+(x+3)^2-5(x+7)(x-7)=0
1, tìm x :
a) (x+2).(x+3)-(x-2).(x+5)=0
b) (2x+3).(x-4)+(x-5).(x-2)=(x-4).(3x-5)
c) (3x-5).(7-5x)-(5x+2).(2-3x)=3
d)(x-7).(x+7)-(x-4)2-x=10+3
e) (x+1/2)2-(x-1).(x+1)=2x-1
2, Thu gọn :
a) (x+5)2-(3-x)2-2(x-4).(x+4)
b)4(x-1)2+(2x+3)2-8(x-2)(x+2)
a)(2x-1)^2+(x+3)^2-5(x+7)(x-7)=0
b)(x+2)(x^2-2x+4)-x(x^2+2)=15
c)(x+3)^3-x(3x+1)^2+(2x-1)(4x^2-2x+1)=28
d)(x^2-1)^3-(x^4+x^2+1)(x^2-1)=0
Tìm x biết
a) (x-3)2 - 4 = 0
b) (2x-1)2 + (x+3)2 - 5(x+7)(x-7) = 0
Tìm x biết
a,25x mũ 2 - 9=0
b,(x + 4)mũ 2 - (x+1)(x-1)=16
c,(2x-1)mũ 2+(x+3)mũ 2 - 5(x+7)(x-7)=0
Tìm x, biết :
a. ( 2x - 1 )2 + ( x + 3 )2 - 5 . ( x + 7 ) . ( x - 7 ) = 0
b. 4x2 - 4x = -1
1, tìm x :
a) (x+2).(x+3)-(x-2).(x+5)=0
b) (2x+3).(x-4)+(x-5).(x-2)=(x-4).(3x-5)
c) (3x-5).(7-5x)-(5x+2).(2-3x)=3
d)(x-7).(x+7)-(x-4)2-x=10+3
e) (x+1/2)2-(x-1).(x+1)=2x-1
2, Thu gọn :
a) (x+5)2-(3-x)2-2(x-4).(x+4)
b)4(x-1)2+(2x+3)2-8(x-2)(x+2)
a)(x-4)(x+4)-(1+2x)2
b)(3-2y)2-(y-6)(y+6)
c)3x(x-5)-(x+7)(x-7)
