Question

TÌM SỐ NGUYÊN X BIẾT 

7✖( 5 - 2x ) - 13 = 3x - 83

x²  + 3x = 2x + 6

x² - 7x + 12 = 0

Answer 1

\(35-14x-13-3x+83=0\\ -17x+105=0\\ -17x=-105\\ x=\dfrac{105}{17}\\ b,x^2+3x-2x-6=0\\ x^2+x-6=0\\ x^2-2x+3x-6=0\\ x\left(x-2\right)+3\left(x-2\right)=0\\ \left(x+3\right)\left(x-2\right)=0\)

=> x = - 3; x= 2

\(x^2-4x-3x+12=0\\ x\left(x-4\right)-3\left(x-4\right)=0\\ \left(x-3\right)\left(x-4\right)=0\)

=> x = 3 ; x=4

Answer 2

giúp

Answer 3

`7 xx (5-2x) - 13 = 3x - 83`

`35 - 10x - 13 = 3x - 83`

`13x = 105`

`=> x = 7`.

`b, x^2 + 3x = 2x + 6`

`x(x+3) = 2(x+3)`

`=>` Ptr vô nghiệm.

`c, x^2 - 7x + 12 = 0`

`x^2 - 2 . 7/2 x + 49/4 = 1/4`

`=> (x-7/2)^2 = +-1/2^2`

`=> x = 4` hoặc `3`.