Gio is solving the quadratic equation by completing the square

quadratic-equation

#1

Gio is solving the quadratic equation by completing the square.

5x2 + 15x – 4 = 0

What should Gio do first?

Isolate the constant.
Factor 5 out of the variable terms.
Isolate the variable x.
Add 9 to both sides of the equation.

Answer:

Factor 5 out of the variable terms.

5x^2+15x-4=0
this equation has discriminant=b^2-4ac=(1515)-(4)(5)*(-4)=305
discriminant is positive and not a perfect the roots are irrational and they are distinct.
so to find roots its better that u use the formula,
root 1=(-b+sqrt(discriminant))/2a and root 2=(-b-sqrt(discriminant))/2a where a,b,c are coeficients 0f x^2,x and x^0 of given equation.
i m not saying that it is the only method for solving this problem.but for given equation this method gives solution easily than any other methods u mentioned in your question.