Question

5x^2-22x-15=0 плиззз​

Answer 1

$displaystyle tt 5x^2-22x-15=0\\a=5,:::b=-22,:::c=-15\\displaystyle tt D=b^2-4ac=(-22)^2-4cdot5cdot(-15)=484+300=784\\ displaystyle tt sqrt{D}=sqrt{784}=28\\displaystyle tt bold{x_1}}=frac{-b+sqrt{D}}{2a}=frac{22+28}{2cdot5}=frac{50}{10}=5\\ displaystyle tt bold{x_2}}=frac{-b+sqrt{D}}{2a}=frac{22-28}{2cdot5}=frac{-6}{10}=-0,6$