Question

5x^2-22x-15=0 плиззз​

Answer 1

$\displaystyle \tt 5x^2-22x-15=0\\\\a=5,\:\:\:b=-22,\:\:\:c=-15\\\\\displaystyle \tt D=b^2-4ac=(-22)^2-4\cdot5\cdot(-15)=484+300=784\\\\ \displaystyle \tt \sqrt{D}=\sqrt{784}=28\\\\\displaystyle \tt \bold{x_1}}=\frac{-b+\sqrt{D}}{2a}=\frac{22+28}{2\cdot5}=\frac{50}{10}=5\\\\ \displaystyle \tt \bold{x_2}}=\frac{-b+\sqrt{D}}{2a}=\frac{22-28}{2\cdot5}=\frac{-6}{10}=-0,6$