Question

7x^2=9+x what are the values of x

Will give medal and points

Answer 1

7x² = 9 + x Subtract x from both sides
7x² - x = 9 Subtract 9 from both sides
7x² - x - 9 = 0 Use the Quadratic Formula

a = 7 , b = -1 , c = -9

x =
`(-b \pm √(b^2 - 4ac) )/(2a)` Plug in the a, b, and c values
x =
`(- (-1) \pm √((-1)^2 - 4(7)(-9)) )/(2(7))` Cancel out the double negative
x =
`(1 \pm √((-1)^2 - 4(7)(-9)) )/(2(7))` Square -1
x =
`(1 \pm √(1 - 4(7)(-9)) )/(2(7))` Multiply 7 and -9
x =
`(1 \pm √(1 - 4(-63) )/(2(7))` Multiply -4 and -63
x =
`(1 \pm √(1 + 252) )/(2(7))` Multiply 2 and 7
x =
`(1 \pm √(1 + 252) )/(14)` Add 1 and 252
x =
`(1 \pm √(253) )/(14)` Split up the
`\pm`
x =
`\left \{ {{ (1 + √(253) )/(14) } \atop { (1 - √(253) )/(14) }} \right.`
The approximate square root of 253 is 15.905973.
x ≈
`\left \{ { (1 + 15.905973)/(14) } \atop { (1 - 15.905973)/(14) }} \right` Add and subtract
x ≈
`\left \{ {{ (16.905973)/(14) } \atop { (14.905973)/(14) }} \right.` Divide
x ≈
`\left \{ {{1.2075} \atop {1.0647}} \right.` Round to the nearest hundredth
x ≈
`\left \{ {{1.21} \atop {1.06}} \right.`