Question

2x^2-7x-15=0 решите уравнение

Answer 1

2x^2-7x-15=0
D=(-7)^2-(-4*(2*15))=169
x₁=7+√169/4=5
x₂=7-√169/4=-1,5

Answer 2

$2x^2-7x-15=0 \\ a=2;b=-7;c=-15 \\ \Delta=b^2-4ac=(-7)^2-4*2*(-15)= 49+120=169=13^2 \\ x_1= \frac{-b- \sqrt{\Delta} }{2a}= \frac{7-13}{2*2}=- \frac{6}{4}=- \frac{3}{2} \\ x_2= \frac{-b+ \sqrt{\Delta} }{2a}= \frac{7+13}{4}= \frac{20}{4}=5$