Question

(3x-5)(3x+5) = 45x-79

Answer 1

$3x \cdot 3x +5 \cdot 3x -5 \cdot 3x -25=45x-79 \\ \\ 9x^2 +15x-15x-25=45x-79 \\ \\9x^2 -45x-25+79=0 \\ \\ 9x^2 -45x+54=0 \ \ \ : | 9 \\ \\ x^2-5x+6=0; \ \ x_{1,2}=\frac{-b \pm \sqrt{b^2 - 4 \cdot a \cdot c}}{2a}=\frac{5 \pm \sqrt{25-24}}{2}=\frac{5 \pm 1}{2} \\ \\ x_1=3; \ \ x_2=2$

Answer 2

(3х-5)(3х+5)=45х-79
9х²-25=45х-79
9х²-45х+54=0
х²-5х+6=0
D=25-24=1
x₁=(5+1):2=3
x₂=(5-1):2=2
Ответ:2 и 3