Question

(4x+3)•(x-12)-39x=7 розв'язання рівняння

Answer 1

$\displaystyle \tt (4x+3)(x-12)-39x=7\\\displaystyle \tt 4x^2-48x+3x-36-39x=7\\\displaystyle \tt 4x^2-84x-36=7\\\displaystyle \tt 4x^2-84x-36-7=0\\\displaystyle \tt 4x^2-84x-43=0\\\displaystyle \tt 2x(2x+1)-43(2x+1)=0\\\displaystyle \tt (2x+1)(2x-43)=0\\\\ \displaystyle \tt 2x+1=0\\\displaystyle \tt 2x=-1\\\displaystyle \tt x=-1\div2\\\displaystyle \tt \bold{x_1=-0,5}\\\\ \displaystyle \tt 2x-43=0\\\displaystyle \tt 2x=43\\\displaystyle \tt x=43\div2\\\displaystyle \tt \bold{x_2=21,5}$