a) \(A=3\left(x+5\right)+x^2\)

Thay x = 1 vào A, ta được:

\(A=3\left(1+5\right)+1^2\)

\(A=3.6+1\)

\(A=19\)

b) \(B=3x\left(x+2\right)-x\left(x+1\right)\)

Thay x = -1 vào B, ta được:

\(B=3.\left(-1\right)\left(-1+2\right)-\left(-1\right)\left(-1+1\right)\)

\(B=-3-0\)

\(B=-3\)

c) \(C=7x\left(x-5\right)+3\left(x-2\right)\)

Thay x = 0 vào C, ta được:

\(C=7.0.\left(0-5\right)+3.\left(0-2\right)\)

\(C=0+3.\left(-2\right)\)

\(C=-6\)

d) \(D=-2x\left(x+1\right)+4\left(x+2\right)\)

Thay x = -1 vào D, ta được:

\(D=-2\left(-1\right)\left(-1+1\right)+4\left(-1+2\right)\)

\(D=0+4\)

\(D=4\)

e) \(E=x^2-x+2x\left(x+3\right)\)

Thay x = 2 vào E, ta được:

\(E=2^2-2+2.2\left(2+3\right)\)

\(E=4-2+4.5\)

\(E=22\)

f) \(F=5-4x\left(x-2\right)\)

Thay x = -1 vào F, ta được:

\(F=5-4.\left(-1\right)\left(-1-2\right)\)

\(F=5-12\)

\(F=-7\)

g) \(G=x\left(x-5\right)-2x\left(x+1\right)+x^2\)

Thay x = -2 vào G, ta được:

\(G=-2\left(-2-5\right)-2.\left(-2\right)\left(-2+1\right)+\left(-2\right)^2\)

\(G=14-4+4\)

\(G=14\)

h) \(H=x\left(7x+2\right)-5x\left(x+3\right)\)

Thay x = 1 vào H, ta được:

\(H=1\left(7.1+2\right)-5.1\left(1+3\right)\)

\(H=9-20\)

\(H=-11\)

i) \(I=3x^2-2x\left(x-5\right)+x\left(x-7\right)\)

Thay x = 10 vào I, ta được:

\(I=3.10^2-2.10\left(10-5\right)+10.\left(10-7\right)\)

\(I=300-100+30\)

\(I=230\)

thu gọn rồi mới tính bạn nha

Giải:

a) \(B=3x\left(x+2\right)-x\left(x+1\right)\)

Tại x = -1, ta được:

\(B=3\left(-1\right)\left(-1+2\right)-\left(-1\right)\left(-1+1\right)\)

\(\Leftrightarrow B=-3-0=-3\)

b) \(C=7x\left(x-5\right)+3\left(x-2\right)\)

Tại x = 0, ta được:

\(C=7.0\left(0-5\right)+3\left(0-2\right)\)

\(\Leftrightarrow C=0+\left(-6\right)=-6\)

c) \(D=-2x\left(x+1\right)+4\left(x+2\right)\)

Tại x = -1, ta được:

\(D=-2\left(-1\right)\left(-1+1\right)+4\left(-1+2\right)\)

\(\Leftrightarrow D=0+4=4\)

d) \(E=x\left(x-5\right)-2x\left(x+1\right)+x^2\)

Tại x = -2, ta được:

\(E=-2\left(-2-5\right)-2\left(-2\right)\left(-2+1\right)+\left(-2\right)^2\)

\(\Leftrightarrow E=14-4+4=14\)

e) \(F=x\left(7x+2\right)-5x\left(x+3\right)\)

Tại x = 1, ta được:

\(F=1\left(7.1+2\right)-5.1\left(1+3\right)\)

\(F=9-20=-11\)

Vậy ...

\(B=3x\left(x+2\right)-x\left(x+1\right)\)

\(B=3x^2+6x-x^2-x\)

\(B=2x^2+5x\)

\(B=x\left(2x+5\right)\)

Tại x = -1 ta có :

\(B=\left(-1\right)\left[2.\left(-1\right)+5\right]=\left(-1\right).3=-3\)

\(C=7x\left(x-5\right)+3\left(x-2\right)\)

\(C=7x^2-35x+3x-6\)

\(C=7x^2-32x-6\)

Tại x=0 ta có :

\(C=7.0-32.0+6=6\)

\(D=-2x\left(x+1\right)+4\left(x+2\right)\)

\(D=-2x^2-2x+4x+8\)

\(D=-2x^2+2x+8\)

\(D=-2\left(x^2-x-4\right)\)

Tại x = -1 ta có :

\(D=-2.\left[\left(-1\right)^2-\left(-1\right)-4\right]=4\)

\(E=x\left(x-5\right)-2x\left(x+1\right)+x^2\)

\(E=x^2-5x-2x^2-2x+x^2\)

\(E=-7x\)

Tại x = -2 ta có :

\(E=-7\left(-2\right)=14\)

\(F=x\left(7x+2\right)-5x\left(x+3\right)\)

\(F=7x^2+2x-5x^2-15x\)

\(F=2x^2-13x=x\left(2x-13\right)\)

Tại x= 1 ta có :

\(F=1.\left(2.1-13\right)=-11\)

a) Thay x=1:

\(9.1^2+12.1+49=70\)

b) Thay x=-2 và y=3:

\(25.\left(-2\right)^2-10\left(-2\right).3+3^2\)\(=169\)

c)Thay x=-10:

\(\left(-10\right)^3+15\left(-10\right)^2+75\left(-10\right)+125=-125\)

d) Thay x=13:

\(13^3-9.13^2+27.13-27=1000\)

e) Thay x=-2:

\(\left(-2-1\right)^3-4\left(-2\right)\left(-2+1\right)\left(-2-1\right)+3\left(-2-1\right)\left[\left(-2\right)^2-2+1\right]\)=-30

f) Thay x=1:

\(\left(1-1\right)\left(1-2\right)\left(1+1+1\right)\left(4+2+1\right)=0\)

\(9x^2+12x+49=\left(9x^2+12x+4\right)+45=\left(3x+2\right)^2+45=5^2+45=25+45=70\)

\(25x^2-10xy+y^2=\left(5x-y\right)^2=\left(-13\right)^2=169\)

\(x^3+15x^2+75x+125=\left(x^3+5x^2\right)+\left(10x^2+50x\right)+\left(25x+125\right)=x^2\left(x+5\right)+10x\left(x+5\right)+25\left(x+5\right)=\left(x+5\right)^2\left(x+5\right)=\left(x+5\right)^3=-125\)

\(x^3-9x^2+27x-27=\left(x^3-3x^2\right)-\left(6x^3-18x\right)+\left(9x-27\right)=x^2\left(x-3\right)-6x\left(x-3\right)+9\left(x-3\right)=\left(x-3\right)^3=1000\)

\(x=1\Rightarrow x-1=0\Rightarrow\left(x-1\right)\left(x-2\right)\left(1+x+x^2\right)\left(4+2x+x^2\right)=0\)

a: \(A=77^2+77\cdot22+77=7700\)

b: \(B=2\cdot\left(1.007+0.006\right)+2\left(-0.006-1.007\right)\)

\(=0\)

c: \(C=\left(x-1\right)\left(x^2-4x+4\right)\)

\(=\left(x-1\right)\left(x-2\right)^2=\left(3-1\right)\cdot\left(3-2\right)^2=2\)

d: \(D=\left(-5\right)^2\cdot2-2+\left(-5\right)\cdot2^2+5\)

\(=25\cdot2-2-5\cdot4+5\)

=50-2-20+5

=55-22=33

,(3x-1) mũ 2=9/16
<=> (3x-1)^2 = ( ±3/4)^2
<=> l3x-1l  = 3/4
Hoặc 3x-1 = 3/4
 <=> 3x= 3/4 + 1
<=> x = 7/4 : 3
<=> x= 7/1

1) Ta có: \(2\left(x-y\right)+\left(x-y\right)^2+\left(y-x\right)^2\)

\(=2\left(-3-1000\right)+\left(-3-1000\right)^2+\left(3+1000\right)^2\)

\(=-2006+1006009+1006009\)

\(=2010012\)

2) \(x^3+12x^2+48x+64\)

\(=x^3+3.x^2.4+3.x.4^2+4^3\)

\(=\left(x+4\right)^3=\left(6+4\right)^3=10^3=1000\)

3) \(x^3-6x^2+12x-8\)

\(=x^3-3.x^2.2+3.x.2^2-2^3\)

\(=\left(x-2\right)^3=\left(22-2\right)^3=20^3=8000\)

\(2\left(x-y\right)+\left(x-y\right)^2+\left(y-x\right)^2\)

=\(2\left(x-y\right)+\left(x-y+y-x\right)\left(x-y-\left(y-x\right)\right)\)

= \(2\left(x-y\right)+\left(x-y+y-x\right)\left(x-y-y+x\right)\)

= \(2\left(x-y\right)\)

Thay x = -3,y = 1000 vào ta có : 2(x - y) = 2(-3 - 1000) = 2.(-1003) = -2006

\(x^3+12x^2+48x+64\)

\(=x^3+3\cdot x^2\cdot4+3\cdot x\cdot4^2+4^3=\left(x+4\right)^3\)

Thay x = 6 vào ta có : (6 + 4)³ = 10³ = 10000

\(x^3-6x^2+12x-8=x^3-3x^2\cdot2+3x\cdot2^2-2^3\)

\(=\left(x-2\right)^3\)

Thay x = 22 vào ta có : (22 - 2)³ = 20³ = 8000

a) 2( x - y ) + ( x - y )² + ( y - x )²

= 2( x - y ) + ( x - y )² + ( x - y )²

= ( x - y )[ 2 + ( x - y ) + ( x - y ) ]

= ( x - y )( 2 + x - y - x - y )

= ( x - y )( 2x - 2y + 2 )

= 2( x - y )( x - y + 1 )

Thế x = -3 ; y = 1000 ta được

2( -3 - 1000 )( -3 - 1000 + 1 ) = 2010012

b) x³ + 12x² + 48x + 64 = ( x + 4 )³ 

Thế x = 6 ta được ( 6 + 4 )³ = 10³ = 1000

c) x³ - 6x² + 12x - 8 = ( x - 2 )³

Thế x = 22 ta được ( 22 - 2 )³ = 20³ = 8000