Question

Pentru ecuatia x patrat -7x+10=0 suma radacinilor este?

Answer 1

$x^2-7x+10=0 \\ \Delta=b^2-4ac=(-7)^2-4\cdot1\cdot10=49-40=9 \\ \Delta > 0, \ \ \Rightarrow \\ x_{1,2}=\frac{-b \pm \sqrt{\Delta}}{2a}=\frac{-(-7) \pm \sqrt {9}}{2\cdot 1}=\frac{7\pm3}{2} \\ \Rightarrow x_1=\frac{10}{2}=5; \ \Rightarrow x_2=\frac{4}{2}=2; \\ \Rightarrow \boxed{x_1+x_2=5+2=\boxed{7}}$