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Thực hiện tính các phép tính sau :
- 2y(3y3 +4y -18)
- (3y+x)(x-3y)
- (4+x)2
các bạn cố trả lời giúp mk nha!!!
Giải:
4xn (7xn-1 + x - 5) - 2xn-2 (14xn+1 - 10x2)
= 28x2n-1 +4xn + 1 – 20xn - 28x2n-1 + 20xn
= 4xn+1
a,3xn(6xn−3+1)−2xn(9xn−3−1)a,3xn(6xn−3+1)−2xn(9xn−3−1)
=xn[3(6xn−3+1)−2(9xn−3−1)]=xn[3(6xn−3+1)−2(9xn−3−1)]
=xn(18xn−3+3−18xn−3+2)=xn(18xn−3+3−18xn−3+2)
=5xn=5xn
b,5n+1−4.5nb,5n+1−4.5n=5n.5+5n.4=5n(5+4)=45n=5n.5+5n.4=5n(5+4)=45n
c,62.64−43(36−1)c,62.64−43(36−1)
=66−43.36+43=66−43.36+43
=26.36−43.36+43=26.36−43.36+43
=36(26−43)+43=36(26−43)+43
=36[(22)3−43]+43=36.0+43=43=64
~Hok tốt~
TL:
a)
=\(18x^{2n-3}+3x^n-18x^{2n-3}+2x^n\)
=\(6x^n\)
b)
=\(5^n.5-4.5^n\)
=\(5^n\left(5-4\right)\)
=\(5^n\)
vậy.......
hc tốt
a) 2(x-1)2 - 4(x+3)2 + 2x(x-5)
= 2(x2 -2x +1)- 4(x2 + 6x +9) + 2x2 -10x
= 2x2 - 4x + 2 -4x2 - 24x - 36 + 2x2 - 10x
= (2x2 + 2x2 - 4x2) - (4x + 24x+10x) +(2-36)
= -38x-34
b) 2(2x+5)2 -3(4x+1)(1-4x)
= 2(4x2 + 20x + 25) + 3(4x+1)(4x-1)
= 8x2 +40x + 50 + 3(16x2 -1)
= 8x2 + 40x + 50 + 48x2 - 3
=56x2 +40x + 47
a, \(2\left(x-1\right)^2-4\left(x+3\right)^2+2x\left(x-5\right)\)
\(=2\left(x^2-2x+1\right)-4\left(x^2+6x+9\right)+2x\left(x-5\right)\)
\(=2x^2-4x+2-4x^2-24x-36+2x^2-10=-28x-44\)
b, \(2\left(2x+5\right)^2-3\left(4x+1\right)\left(1-4x\right)\)
\(=2\left(4x^2+20x+25\right)-3\left(1-16x^2\right)\)
\(=8x^2+40x+50-3+48x^2=56x^2+40x+47\)
a) \(2x^2\left(3x-5\right)=2x^2.3x-2x^2.5=6x^3-10x^2\)
b) \(\left(12x^3y+18x^2y\right):2xy\)\(=12x^3y:2xy+18x^2y:2xy\)
\(=6x^2+9x=3x\left(2x+3\right)\)
\(3x\left(x-5\right)-x\left(4+3x\right)=43\)
\(\Leftrightarrow3x^2-15x-4x-3x^2=43\)
\(\Leftrightarrow-19x=43\)
\(\Leftrightarrow x=\frac{-43}{19}\)