i hope this helps you
ax^2+bx+c=0
disctirminant =b^2-4ax
x1,2=-b+- square root of disctirminant /2a
a=1 b=-7 c=1
disctirminant =(-7)^2-4.1.1
disctirminant =49-4=45
x1=-(-7)+square root of 45/2.1
x1=7+3 square root of 5/2
x2=-(-7)-square root of 45/2.1
x2=7-3 square root of 5/2
