x(2x-3)-6+4x=0 (2x-1)^2 - 25 =0 x^3 + 5x^2-4x-20=0 (x-2)^2 - (x-3)(x+3)=6 x^2 - x - 6=0 2x^2 + 3x=5 (x-2)(3x+5)=4

Đáp án:

↓↓

Giải thích các bước giải:

`a)`

`x (2x - 3) - 6 + 4x = 0`

`-> 2x² - 3x - 6 + 4x = 0`

`-> (2x² + 4x) - (3x + 6) = 0`

`-> 2x (x - 2) + 3 (x - 2) = 0`

`-> (2x + 3)(x - 2) = 0`

`->`\(\left[ \begin{array}{l}2x + 3 = 0\\x - 2 = 0\end{array} \right.\)

`->`\(\left[ \begin{array}{l}x=-3\\x=2\end{array} \right.\)

`b)`

`(2x - 1)^2 - 25 = 0`

`-> (2x - 1)^2 - 5^2 = 0`

`-> (2x - 1 - 5)(2x - 1 + 5) = 0`

`-> (2x - 6)(2x + 4) = 0`

`->`\(\left[ \begin{array}{l}x=3\\x=-2\end{array} \right.\)

`c)`

`x^3 + 5x^2 - 4x - 20 = 0`

`-> (x^3 + 5x^2) - (4x + 20) = 0`

`-> x^2 (x + 5) - 4 (x + 5) = 0`

`-> (x^2 - 4)(x + 5) = 0`

`-> (x - 2)(x + 2)(x + 5) = 0`

`->`\(\left[ \begin{array}{l}x - 2 = 0; x + 2 = 0\\x + 5 = 0\end{array} \right.\)

`->`\(\left[ \begin{array}{l}x = 2; x = -2\\x=-5\end{array} \right.\)

`d)`

`(x - 2)^2 - (x - 3)(x + 3) = 6`

`-> (x^2 - 4x + 4) - (x^2 - 9) = 6`

`-> x^2 - 4x + 4 - x^2 + 9 = 6`

`-> 13 - 4x = 6`

`-> 4x = 7`

`-> x = 7/4`

`e)`

`x^2 - x - 6 = 0`

`-> (x^2 + 2x) - (3x + 6) = 0`

`-> x (x + 2) - 3 (x + 2) = 0`

`-> (x - 3)(x + 2) = 0`

`->`\(\left[ \begin{array}{l}x - 3 = 0\\x + 2 = 0\end{array} \right.\)

`->`\(\left[ \begin{array}{l}x=3\\x=-2\end{array} \right.\)

`g)`

`2x^2 + 3x = 5`

`-> 2x^2 + 3x - 5 = 0`

`-> (2x^2 - 2x) + (5x - 5) = 0`

`-> 2x (x - 1) + 5 (x - 1) = 0`

`-> (2x + 5)(x - 1) = 0`

`->`\(\left[ \begin{array}{l}2x + 5 = 0\\x - 1 = 0\end{array} \right.\)

`->`\(\left[ \begin{array}{l}x = -5/2\\x=1\end{array} \right.\)

`h)`

`(x - 2)(3x + 5) = 4`

`-> (x - 2)(3x + 5) - 4 = 0`

`-> x (3x + 5) - 2 (3x + 5) - 4 = 0`

`-> 3x^2 + 5x - 6x - 10 - 4 = 0`

`-> 3x^2- x - 14 = 0`

`-> (3x^2 + 6x) - (7x + 14) = 0`

`-> 3x (x + 2) - 7 (x + 2) = 0`

`-> (3x - 7)(x + 2) = 0`

`->`\(\left[ \begin{array}{l}3x - 7 = 0\\x + 2 = 0\end{array} \right.\)

`->`\(\left[ \begin{array}{l}x = 7/3\\x = -2\end{array} \right.\)