1.Tìm số nguyên x,biết:
a) 5(x - 2) - 3x = -4

=> 5x - 5 . 2 - 3x = -4

=> 5x - 10 - 3x = -4

=> (5x - 3x) - 10 = -4

=> 2x - 10 = -4

=> 2x = -4 + 10

=> 2x = 6

=> x = 6 : 2

=> x = 3

b) (x - 3) . (x + 4) < 0

=> \(\left[\begin{matrix}x-3=0\\x+4=0\end{matrix}\right.=>\left[\begin{matrix}x=0+3\\x=0-4\end{matrix}\right.=>\left[\begin{matrix}x=3\\x=-4\end{matrix}\right.\)

=> -4 < x < 3

\(D=\left(196-1^2\right)\left(196-2^2\right)\left(196-3^2\right)...\left(196-19^2\right)\)                                               \(D=\left(196-1^2\right)\left(196-2^2\right)\left(196-3^2\right)...\left(196-14^2\right)...\left(196-19^2\right)\)            \(D=\left(196-1^2\right)\left(196-2^2\right)\left(196-3^2\right)...0...\left(196-19^2\right)\)                                        \(D=0\)            

1a,5(x-2)-3x=4

5x-10-3x=4

2x-10=4

2x=4+10

2x=14

x=7

1a,5.(x-2)-3x=-4
5x-10-3x=-4
2x-10=-4
2x= -4+10
2x=6
x=3

g: =193-127+96-196-196+127=-3-100=-103

h: \(=25\cdot9-31+12-16+13=225-22=203\)

i: \(=4^2+378-3^3\cdot1=16-27+378=367\)

Chú ý rằng trong tích có thừa số 196-14²

Mà 196-14²=196-196=0

Vậy tích bằng 0

Trả lời:

\(\left(196-1^2\right).\left(196-2^2\right).....\left(196-25^2\right)\)

\(=\left(196-1^2\right).\left(196-2^2\right).....\left(196-14^2\right).....\left(196-25^2\right)\)

\(=\left(196-1^2\right).\left(196-2^2\right).....\left(196-196\right).....\left(196-25^2\right)\)

\(=\left(196-1^2\right).\left(196-2^2\right).....0.\left(196-25^2\right)\)

\(=0\)

Hok tốt!

Good girl

\(\left(196-1^2\right).\left(196-2^2\right)....\left(196-20^2\right)\)

ta có \(196=14^2\)

Mà Trong biểu thức trên  có hiệu là (196-\(14^2\))

=> Biểu thức trên = 0

mình nghĩ thế

Trả lời:

\(\left(196-1^2\right).\left(196-2^2\right).....\left(196-20^2\right)\)

\(=\left(196-1^2\right).\left(196-2^2\right).....\left(196-14^2\right).....\left(196-20^2\right)\)

\(=\left(196-1^2\right).\left(196-2^2\right).....\left(196-196\right).....\left(196-20^2\right)\)

\(=\left(196-1^2\right).\left(196-2^2\right).....0.\left(196-20^2\right)\)

\(=0\)

Hok tốt!

Good girl

    (196-1²).(196-2²)....(196-14²).(196-15²)...(196-20²)

=      (196-1²).(196-2²)....(196-196).(196-15²)...(196-20²)

=      (196-1²).(196-2²)....0.(196-15²)...(196-20²)

=                             0

làm ny anh nhé baby

người ta hỏi bài mà nói zậy là sao?

Flo đó

\(9M=3^2+3^4+3^6+...+3^{196}+3^{198}\)

\(\Leftrightarrow8M=3^{198}-1\)

\(\Leftrightarrow M=\dfrac{3^{198}-1}{8}\)