Question

Solve the quadratic equation:

X? + 7x+10=0
x= -10, 7
X= 5, 2
x= -4,-1
X=-5, -2
help?

Answer 1

The last x=-5 or x=-2

Explanation:

`x^2+7x+10=0\qquad\implies\quad a=1\,,\ b=7\,,\ c=10\\\\\\x=(-b\pm√(b^2-4ac))/(2a)=(-7\pm√(7^2-4(1)(10)))/(2(1))=(-7\pm√(49-40))/(2)=(-7\pm\sqrt9)/(2)\\\\ x_1=\frac{-7+3}2=\frac{-4}2=-2\,,\qquad x_1=\frac{-7-3}2=\frac{-10}2=-5`