Question

Write a quadratic equation in standard form such that -5 is it's only solution.

Answer 1

 

$\displaystyle\bf\\x_1=x_2=-5\\\\(x-x_1)(x-x_2)=0\\\\(x-(-5))(x-(-5))=0\\\\(x+5)(x+5)=0\\\\x^2+2\cdot x\cdot5 + 5^2=0\\\\\boxed{\bf x^2+10x + 25=0}$