Question

$sqrt{35-5x} +2X=9$

Answer 1

ОДЗ
$left { {{35-5x geq 0} atop {9-2x geq 0}} right. <=> left { {{5xleq35} atop {2x leq 9}} right.<=> left { {{xleq7} atop {x leq 4,5}} right.\ \ (- infty; 4,5]$

$sqrt{35-5x}+2x=9\ sqrt{35-5x}=9-2x\ (sqrt{35-5x})^2=(9-2x)^2\ 35-5x=81-36x+4x^2\ 4x^2-31x+46=0\ D=961-736=225\ x_1=frac{31+15}{8}=5frac{3}{4}\ x_2=frac{31-15}{8}=2$
x₁ не удовлетворяет ОДЗ
Ответ 2