Question

Which equation shows the quadratic formula used correctly to solve 7x^2=9+x for x?

Answer 1

7x^2 = 9 + x
7x^2 - x - 9 = 0

(1 +/-√ -1^2 - 4(7)(-9)) / 2(7)

(1 +/-√ 1 + 252) / 14

(1 +/-√ 252) / 14


x =1/14 + 1/14 √253
x=1/14 + −1/14 √253

Answer 2

`x=(1-√(253))/(14),(1+√(253))/(14)`

Explanation:

Given:
`7x^2=9+x`

Standard form of quadratic equation:

`ax^2+bx+c=0`

`7x^2-x-9=0`

Quadratic formula:

`x=(-b\pm√(b^2-4ac))/(2a)`

where,

• a is coefficient of x², a=7
• b is coefficient of x, b=-1
• c is constant term, c=-9

Substitute the value into formula

`x=(1\pm√(1^2-4(7)(-9)))/(2(7))`

`x=(1\pm√(253))/(14)`

`x=(1-√(253))/(14),(1+√(253))/(14)`

Hence, All the above steps to solve for x using quadratic formula.