\(\left[\left(6x-72\right):2-84\right].28=5628\)
Help me ! Đề bài là Tìm x nha , giúp vs ! Mai đi hc r`
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a, \(\left(2600+6400\right)-3x=1200\)
\(\Rightarrow9000-3x=1200\)
\(\Rightarrow3x=7800\)
\(\Rightarrow x=2600\)
b, \(\left[\left(6x-72\right):2-84\right].28=5628\)
\(\Rightarrow\left(6x-72\right):2-84=201\)
\(\Rightarrow\left(6x-72\right):2=285\)
\(\Rightarrow6x-72=570\)
\(\Rightarrow6x=642\)
\(\Rightarrow x=107\)
a) (2600 + 6400) - 3x = 1200
9000 - 3x = 1200
3x = 9000 - 1200
3x = 7800
x = 2600
Vậy x = 2600
b) [(6x - 72) : 2 - 48].28 = 5628
(6x - 72) : 2 - 48 = 5628 : 28
(6x - 72) : 2 - 48 = 201
(6x - 72) : 2 = 201 + 48
(6x - 72) : 2 = 249
6x - 72 = 249.2
6x - 72 = 498
6x = 498 + 72
6x = 570
x = 570 : 6
x = 95
Vậy x = 95
(6x-72) : 2 - 84 = 5628:28
(6x-72):2-84= 201
(6x -72):2= 201+84
(6x-72):2= 285
6x-72=285x2
6x-72=570
6x= 570+72
6x= 642
x=642:6
x= 107
[ ( 6x - 72 ) : 2 - 84 ] . 28 = 5628
=> ( 6x - 72 ) : 2 = 201
=> 6x - 72 = 402
=> 6x = 474
=> x = 79
[(6x − 72) : 2 − 84] . 28 = 5628
(6x – 72) : 2 – 84 = 5628 : 28
( 6x – 72) : 2 – 84 = 201
(6x – 72) : 2 = 201 + 84
( 6x – 72) : 2 = 285
6x – 72 = 285.2
6x – 72 = 570
6x = 570 + 72
6x = 642
x = 642 : 6
x = 107
Vậy x = 107
Ta có: \(\left(8x^2-2x+7\right)\left(4x-6x^2-3\right)=\left(6x^2+3x+4\right)\left(9x-8x^2-6\right)\)
\(\Rightarrow\left(8x^2-2x+7\right)\left(4x-6x^2-3\right)-\left(6x^2+3x+4\right)\left(9x-8x^2-6\right)=0\)
\(\Rightarrow14x^3-33x^2+16x+3=0\) (Rút gọn vế đầu)
\(\Rightarrow14x^2\left(x-1\right)-19x\left(x-1\right)-3\left(x-1\right)=0\)
\(\Rightarrow\left(14x^2-19x-3\right)\left(x-1\right)=0\)
\(\Rightarrow\left[7x\left(2x-3\right)+\left(2x-3\right)\right]\left(x-1\right)=0\)
\(\Rightarrow\left(7x+1\right)\left(2x-3\right)\left(x-1\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=-\dfrac{1}{7}\\x=1\\x=\dfrac{3}{2}\end{matrix}\right.\).
Vậy \(x\in\left\{-\dfrac{1}{7};1;\dfrac{3}{2}\right\}.\)
70 - 5(x - 3) = 45
5(x - 3) = 45 - 70
5(x - 3) = -25
x - 3 = (-25) : (-5)
x - 3 = 5
x = 5 + 3
x = 8
Trả lời
1)70-5.(x-3)=45
5.(x-3)=70-45
5.(x-3)=25
x-3 =25:5
x-3 =5
x =5+3
x =8.
2)123-5(x+4)=38
5(x+4)=123-38
5(x+4)=85
x+4 =85:5
x+4 =17
x =17-4
x =13.
3)(3x-24).73=2.74
3x-24 =2.74:73
3x-16 =2.7=14(bước này mk rút gọn nhé)
3x =14+16
3x =30
x =30:3
x =10.
Để mk làm tiếp câu cuối nhé !
a) Xem lại đề.
b) 5. (x - 3)2 + 17 = 142
5. (x - 3)2 = 142 - 17
5. (x - 3)2 = 125
(x - 3)2 = 125 : 5
(x - 3)2 = 25
(x - 3)2 = 52 (cùng số mũ)
⇒ x - 3 = 5
x = 5 + 3 = 8
c) [(6x - 72) : 2 - 84] . 28 = 5628
[(6x - 72) : 2 - 84] = 5628 : 28
[(6x - 72) : 2 - 84] = 201
(6x - 72) : 2 = 201 + 84
(6x - 72) : 2 = 285
6x - 72 = 285. 2
6x - 72 = 570
6x = 570 + 72
6x = 642
x = 642 : 6
x = 107
[(6x - 72):2 - 84].28=5628
(6x - 72):2-84=201
(6x - 72):2 = 285
6x - 72 = 570
6x = 642
x = 107
=.= hok tốt!!
[(6x - 72) : 2 - 84] x 28 = 5628
[(6x - 72) : 2 - 84] = 5628 : 28
[(6x - 72) : 2 - 84] = 201
(6x - 72) : 2 = 201 + 84
(6x - 72) : 2 = 285
6x - 72 = 285 x 2
6x - 72 = 570
6x = 570 + 72
6x = 642
x = 642 : 6
x = 107
Học tốt!!!
b)[(6x-72):2-84]-28=5628
[(6x-72):2-84] = 5628+28
[(6x-72):2-84] = 596
(6x-72) = 596+84
(6x-72) = 680
6x = 680 +72
6x = 752
x =125,333....
b) là
[(6x-72):2-84]-28=5628
[(6x-72):2-84] =5628+28=5656
[(6x-72):2 =5656+84=5740
6x-72 =5740.2
6x-72 =11480
6x =11480+72
6x =11552
x =11552:6=1925,333....
\(\left[\left(6x-72\right):2-84\right].28=5628\)\(\Rightarrow\left(6x-72\right):2-84=5628:28=201\)
\(\Rightarrow\left(6x-72\right):2=201+84=285\)
\(\Rightarrow6x-72=285.2=570\)
\(\Rightarrow6x=570+72=642\)
\(\Rightarrow x=\frac{642}{6}=107\)
[(6x-72):2-84].28=5628
[(6x-72):2-84] =5628:28
[(6x-72):2-84] =201
[(6x-72):2] =201+84
[(6x-72):2] =285
6x-72 =285.2
6x-72 =570
6x =570+72
6x =642
x =642:6
x =107