Tìm x biết
a,5-(x-6)=4(3-2x)
b,3-4x+6(4+x)=x+3(9+x)
c,5x(2x^2-2x+7)=2(-5x^2+5x^3-2x)+3
Tìm x biết a,5-(x-6)=4(3-2x) b,3-4x+6(4+x)=x+3(9+x) c,5x(2x^2-2x+7)=2(-5x^2+5x^3-2x)+3
By Reese
By Reese
Tìm x biết
a,5-(x-6)=4(3-2x)
b,3-4x+6(4+x)=x+3(9+x)
c,5x(2x^2-2x+7)=2(-5x^2+5x^3-2x)+3
Đáp án:
Giải thích các bước giải:
a,5-(x-6)=4(3-2x)
⇒5-x+6=12-8x
⇒11-x=12-8x
⇒-x+8x=12-11
⇒7x=1
⇒x=1/7
vậy x=1/7
b)3-4x+6(4+x)=x+3(9+x)
⇒3-4x+24+6x=x+27+3x
⇒27+2x=4x+27
⇒2x-4x=27-27
⇒-2x=0
⇒x=0
vậy x=0
c)5x(2x^2-2x+7)=2(-5x^2+5x^3-2x)+3
⇒10x³-10x²+35x=-10x²+10x³-4x+3
⇒10x³-10x³-10x²+10x²+35x+4x=3
⇒39x=3
⇒x=3/39
vậy x=3/39
a) 5- ( x – 6 ) = 4 ( 3 – 2 x)
=>5 – x + 6 = 4.3 – 4. 2x
=>( 5 +6) – x= 12 – 8x
=> 11 – x = 12 – 8x
=> -x + 8x = 12 -11
=> x. (-1 + 8)= 1
=> x . 7 = 1
=> x = 1/7
Vậy x = 1/7
b) 3 – 4x + 6 ( 4 +x) = x +3 ( 9+ x)
=>3 – 4x + 6. 4 +6x = x +3. 9+ 3x
=>3 – 4x + 24 + 6x = x + 27+ 3x
=> – 4x + 6x – x – 3x = 27 – 3 – 24
=> x . (-4 + 6 – 1 – 3 )= 0
=> x = 0
Vậy x = 0
c) 5 x ( 2x^2 – 2x + 7 ) = 2 (-5x^2 +5x^3 – 2x )+3
=>5x . 2x^2 – 5x . 2x + 5x . 7 = 2. (-5x^2) + 2.5 x^3 – 2 .2x +3
=> 10x^3 – 10x^2 + 35 x = -10x^2 + 10x^3 – 4x + 3
=>10x^3 – 10x^2 + 35 x + 10x^2 – 10x^3 + 4x = 3
=>( 10x^3 – 10x^3) +(-10x^2+10x^2) +(35x +4x) = 3
=> 0 + 0 +x. (35+4 ) = 3
=> x . 39 = 3
=> x = 3 : 39
=> x = 1/13
Vậy x = 1/13