Question

х2 - 5х = 4х – 20 срочнооо​

Answer 1

$\displaystyle x^2-5x=4x-20\\x^2-5x-4x+20=0\\x^2-9x+20=0\\x^2-4x-5x+20=0\\x(x-4)-5(x-4)=0\\(x-4)(x-5)=0\\x-4=0,x-5=0\\x_{1}=4,x_{2}=5$

Answer 2

$x {}^{2} - 5x = 4x - 20 \\ x {}^{2} - 9x + 20 = 0 \\ a=1~~~~~~~~~b= -9~~~~~~~~~~~~c=20 \\ \left. \begin{cases} { x1 \times x2 = 20 } \\ { x1 + x2 = 9 } \end{cases} \right.\left. \begin{cases} { x1 = 5 } \\ {x2 = 4 } \end{cases} \right. \\ ответ:~~~x1=5~~~~~~~~~~x2=4$