Quadratic formula

Question

Use the Quadratic Formula to solve the equation. (Enter your answers as a comma-separated list.)

42x − 49x² = 9

Answer 1

The quadratic formula is:

So the first step is to put the equation in the form of ax² + bx + c = 0:

42x − 49x² = 9

Add 49x² to both sides and subtract 42x from both sides:

0 = 9 + 49x² - 42x

Rearrange the terms in the proper order:

49x² - 42x + 9 = 0

We can see that a = 49, b = -42 and c = 9. Now, plug those values into the quadratic formula:

x = [-(-42) ± √((-42)² - 4(49)(9))]/(2•49)

x = [42 ± √(1764 - 1764)]/98

x = [42 ± 0]/98

x = 42/98

x = 3/7

Answer 2