Question

1.Tìm số nguyên x,biết:
a) 5(x-2)-3x=-4
b) (x-3).(x+4)<0
2.Tính:
(196-1²).(196-2²).(196-3²)........(196-25²)

Answer 1

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