23.7k views
1 vote
Find the zeros of m(x)=-5x^(2)+50x-135 using quadratic formula with complex numbers

User Secelite
by
6.9k points

1 Answer

5 votes

Answer:


x=5\pm √(2)\:i

Explanation:

The quadratic formula is a mathematical expression used to find the solutions of a quadratic equation of the form ax² + bx + c = 0:


\boxed{\begin{array}{l}\underline{\sf Quadratic\;Formula}\\\\x=(-b \pm √(b^2-4ac))/(2a)\\\\\textsf{when} \;ax^2+bx+c=0 \\\end{array}}

In the case of m(x) = -5x² + 50x - 135:

  • a = -5
  • b = 50
  • c = -135

Substitute the values of a, b and c into the quadratic formula:


x=(-50\pm√(50^2-4(-5)(-135)))/(2(-5))

Simplify:


x=(-50\pm√(2500-2700))/(-10)


x=(-50\pm√(-200))/(-10)

Rewrite 200 as the product of 10², 2 and -1:


x=(-50\pm√(10^2\cdot2\cdot(-1)))/(-10)


\textsf{Apply the radical rule:} \quad √(ab)=\sqrt{\vphantom{b}a}√(b)


x=(-50\pm√(10^2)√(2)√(-1))/(-10)


\textsf{Apply the radical rule:} \quad √(a^2)=a, \quad a \geq 0


x=(-50\pm10√(2)√(-1))/(-10)


\textsf{Apply the imaginary number rule:} \quad √(-1)=i


x=(-50\pm10√(2)\:i)/(-10)

Simplify by dividing the numerator and denominator by the common factor of -10:


x=5\pm √(2)\:i


Therefore, the two solutions of the quadratic equation are:


  • x=5+ √(2)\:i

  • x=5-√(2)\:i
User Peter Turner
by
7.6k points