Multiple choice

Find the roots of the following quadratic equation: $y^2\,=\,3\,+\,4y$

  1. $y\,=\,2\,\pm\,\sqrt2$
  2. $y\,=\,2\,\pm\,\sqrt7$
  3. $y\,=\,2\,\pm\,\sqrt5$
  4. $y\,=\,2\,\pm\,\sqrt6$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Rearrange the equation to y^2 - 4y - 3 = 0. Using the quadratic formula y = (-b +/- sqrt(b^2 - 4ac)) / 2a, we get y = (4 +/- sqrt(16 - 4(1)(-3))) / 2 = (4 +/- sqrt(28)) / 2 = (4 +/- 2*sqrt(7)) / 2 = 2 +/- sqrt(7).

Keep practicing — related questions