Solve:

Question

18x^2 - 21x + 28 = 0?

Answer 1

The quadratic equation is 18x² - 21x + 28 = 0.

Use quadratic formula to find roots of the related quadratic equation.

The solution x = [ - b ±  √ (b² - 4ac) ]/2a.

Compare the given equation with standard form of the quadratic equation ax² + bx + c = 0.

a = 18, b = - 21, and c = 28.

Substitute the values a = 18, b = - 21, and c = 28 in x = [ - b ±  √ (b² - 4ac) ]/2a.

x = [ - (- 21) ±  √ ((- 21)² - 4(18)(28)) ]/2 * 18

x = [  21 ±  √ (441 - 2016) ]/36

x = [  21 ±  √ - 1575 ]/36

x = [  21 ±  √ i²1575 ]/36

x = [  21 ±  3i√525 ]/36

x =(1/12)[ 7 ± 5i√7].

Therefore, solutions of the given quadratic equations are x = (1/12)[ 7 + 5i√7] and (1/12)[ 7 - 5i√7].