Bài 1:

a) \(\Rightarrow3x^2+3x-2x^2-4x+x+1=0\)

\(\Rightarrow x^2=-1\left(VLý\right)\Rightarrow S=\varnothing\)

b) \(\Rightarrow\left(x-2020\right)\left(2x-1\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}x=2020\\x=\dfrac{1}{2}\end{matrix}\right.\)

c) \(\Rightarrow\left(x-10\right)\left(x+2\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}x=10\\x=-2\end{matrix}\right.\)

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

e) \(\Rightarrow\left(x+6\right)\left(x-7\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}x=-6\\x=7\end{matrix}\right.\)

f) \(\Rightarrow\left(5x-4\right)\left(5x+4\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{4}{5}\\x=-\dfrac{4}{5}\end{matrix}\right.\)

Bài 2:

a) \(\Rightarrow3x\left(x^2-4\right)=0\Rightarrow3x\left(x-2\right)\left(x+2\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}x=0\\x=2\\x=-2\end{matrix}\right.\)

b) \(\Rightarrow x\left(x-2\right)+5\left(x-2\right)=0\Rightarrow\left(x-2\right)\left(x+5\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}x=2\\x=-5\end{matrix}\right.\)

1: =>\(5^{x-2}-9=2^4-\left(6^2-6^2\right)\)

=>\(5^{x-2}=16+9=25\)

=>x-2=2

=>x=4

2: \(\Leftrightarrow3^x+16=19^6:19^5-3=19-3=16\)

=>3^x=0

=>x=0

3: \(\Leftrightarrow2^x+2^x\cdot16=272\)

=>2^x*17=272

=>2^x=16

=>x=4

4: \(\Leftrightarrow2^{x-1}+3=24-\left(4^2-2^2+1\right)=24-\left(16-4+1\right)\)

=>\(2^{x-1}+3=24-16+4-1=8+4-1=12-1=11\)

=>2^x-1=8

=>x-1=3

=>x=4

Bài 2: 

a: =>x-1=1 hoặc x-1=-1

=>x=2 hoặc x=0

b: =>x+1=-1

hay x=-2

c: =>(135-7x):9=8

=>135-7x=72

=>7x=63

hay x=9

d: =>(x+7)(x-3)<0

=>-7<x<3

e: \(\Leftrightarrow3^{x-3}=18+9=27\)

=>x-3=3

hay x=6

f: =>4-2x=0

hay x=2

1.a)2.15+37 =30+37=67

  b)43-(25-51)+(42-53+25-51)=43-25+51+42-53+25-51=(43+42)+(-25+25)+(51-51)-53= 85+0+0-53=32

2)3x-5=4                                                b)(2x-8)2=2^4

  3x=4+5                                                     (2x-8).2=16

  x=9:3                                                         (2x-8)=16:2

  x=3                                                             (2x-8)=8

                                                                      2x=8+8

                                                                       2x=16

                                                                      x=16:2

                                                                       x=8

1) Thực hiện phép tính :

a) 2 . 15 + 37 = 30 + 37 = 67 .

b) 43 - (25 - 51) + (42 - 53 + 25 - 51) = 43 - (-26) + (-37) = 43 + 26 - 37 = 32 .

2) Tìm x, biết :

a) 3x - 5 = 4

    3x      = 4 + 5

    3x      = 9

      x      = 9 : 3

      x      = 3

b) (2x - 8) . 2 = 2⁴

    (2x - 8) . 2 = 16

     2x - 8      = 16 : 2

     2x - 8      = 8

     2x           = 8 + 8

     2x           = 16

       x           = 16 : 2

       x           = 8

Đáp số : 1) a) tổng = 67 .

                 b) tổng = 32 .

             2) a) x = 3 .

                 b) x = 8 .

a) Không tồn tại x

b) x = -7

c) x = 2

d) x = 5

a) 7(x - 5) + 2 = 51

\(\Leftrightarrow\) 7(x - 5) = 51 - 2

\(\Leftrightarrow\) 7(x - 5) = 49

\(\Leftrightarrow\) x - 5 = 49 : 7

\(\Leftrightarrow\) x - 5 = 7

\(\Leftrightarrow\) x = 7 + 5

\(\Leftrightarrow\) x = 12.

Vậy x = 12.

k) 2412 : (3x + 147) = |-38| + (-26)

\(\Leftrightarrow\) 2412 : (3x + 147)= 38 + (-26)

\(\Leftrightarrow\) 2412 : (3x + 147)= 12

\(\Leftrightarrow\) 3x + 147 = 2412 : 12

\(\Leftrightarrow\) 3x + 147 = 201

\(\Leftrightarrow\) 3x = 201 - 147

\(\Leftrightarrow\) 3x = 54

\(\Leftrightarrow\) x = 54 : 3

\(\Leftrightarrow\) x = 18.

Vậy x = 18.

I) 4824 : (4x + 137) = |-59| + (-35)

\(\Leftrightarrow\) 4824 :(4x + 137) = 59 + (-35)

\(\Leftrightarrow\) 4824 :(4x + 137) = 24

\(\Leftrightarrow\) 4x + 137 = 4824 : 24

\(\Leftrightarrow\) 4x + 137 = 201

\(\Leftrightarrow\) 4x = 201 - 137

\(\Leftrightarrow\) 4x = 64

\(\Leftrightarrow\) x = 64 : 4

\(\Leftrightarrow\) x = 16.

Vậy x = 16.

c) |-123| - 5(x - 3) = (-28) + 66

\(\Leftrightarrow\) 123 - 5(x - 3) = 38

\(\Leftrightarrow\) 5(x - 3) = 123 - 38

\(\Leftrightarrow\) 5(x - 3) = 85

\(\Leftrightarrow\) x - 3 = 85 : 5

\(\Leftrightarrow\) x - 3 = 17

\(\Leftrightarrow\) x = 17 + 3

\(\Leftrightarrow\) x = 20.

Vậy x = 20.

m) 7x - 4 . 6 = 2058

\(\Leftrightarrow\) 7x - 24 = 2058

\(\Leftrightarrow\) 7x = 2058 + 24

\(\Leftrightarrow\) 7x = 2082

\(\Leftrightarrow\) x = 2082 : 7

\(\Leftrightarrow\) x = \(\frac{2058}{7}\).

Vậy x = \(\frac{2058}{7}\).

Phần b) ra phân số nên mình để mai làm và cả những bài còn lại nữa.

Chúc bạn học tốt !!!

---------------NHANH NHA MK ĐANG CẦN GẤP--------------

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a)A=4(x+11/8)^2 -153/16

Min A=-153/16 khi x=-11/8

b)B=3(x-1/3)^2 -4/3

Min B=-4/3 khi x=1/3

Bài 1:

a) \(A=4x^2+11x-2=\left(4x^2+11x+\dfrac{121}{16}\right)-\dfrac{153}{16}=\left(2x+\dfrac{11}{4}\right)^2-\dfrac{153}{16}\ge-\dfrac{153}{16}\)

\(minA=-\dfrac{153}{16}\Leftrightarrow x=-\dfrac{11}{8}\)

b) \(B=3x^2-2x-1=3\left(x^2-\dfrac{2}{3}x+\dfrac{1}{9}\right)-\dfrac{4}{3}=3\left(x-\dfrac{1}{3}\right)^2-\dfrac{4}{3}\ge-\dfrac{4}{3}\)

\(minB=-\dfrac{4}{3}\Leftrightarrow x=\dfrac{1}{3}\)

Bài 2:

a) \(A=-x^2+3x-1=-\left(x^2-3x+\dfrac{9}{4}\right)+\dfrac{5}{4}=-\left(x-\dfrac{3}{2}\right)^2+\dfrac{5}{4}\le\dfrac{5}{4}\)

\(maxA=\dfrac{5}{4}\Leftrightarrow x=\dfrac{3}{2}\)

b) \(B=-x^2-4x+7=-\left(x^2+4x+4\right)+11=-\left(x+2\right)^2+11\le11\)

\(maxB=11\Leftrightarrow x=-2\)

Bài 1: 

a: Ta có: \(A=4x^2+11x-2\)

\(=4\left(x^2+\dfrac{11}{4}x-\dfrac{1}{2}\right)\)

\(=4\left(x^2+2\cdot x\cdot\dfrac{11}{8}+\dfrac{121}{64}-\dfrac{153}{64}\right)\)

\(=4\left(x+\dfrac{11}{8}\right)^2-\dfrac{153}{16}\ge-\dfrac{153}{16}\forall x\)

Dấu '=' xảy ra khi \(x=-\dfrac{11}{8}\)

b: Ta có: \(B=3x^2-2x-1\)

\(=3\left(x^2-\dfrac{2}{3}x-\dfrac{1}{3}\right)\)

\(=3\left(x^2-2\cdot x\cdot\dfrac{1}{3}+\dfrac{1}{9}-\dfrac{4}{9}\right)\)

\(=3\left(x-\dfrac{1}{3}\right)^2-\dfrac{4}{3}\ge-\dfrac{4}{3}\forall x\)

Dấu '=' xảy ra khi \(x=\dfrac{1}{3}\)