SOLUTION: Hello! Our Lesson is about "ROOTS of QUADRATIC EQUATION". What is the answer here: {{{ (3x+2)^2= 12x + 4.81 }}} Thank you so much!:)Reply ASAP please!^^

Algebra ->  Square-cubic-other-roots -> SOLUTION: Hello! Our Lesson is about "ROOTS of QUADRATIC EQUATION". What is the answer here: {{{ (3x+2)^2= 12x + 4.81 }}} Thank you so much!:)Reply ASAP please!^^      Log On


   

Question 553445: Hello! Our Lesson is about "ROOTS of QUADRATIC EQUATION".
What is the answer here:
+%283x%2B2%29%5E2=+12x+%2B+4.81+
Thank you so much!:)Reply ASAP please!^^
Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
equation is:
(3x+2)^2= 12x + 4.81
multiply out the left hand side of the equation to get:
9x^2 + 12x + 4 = 12x + 4.81
subtract 12x and 4.81 from both sides of the equation to get:
9x^2 - .81 = 0
divide both sides of the equation by 9 to get:
x^2 - .09 = 0
add .09 to both sides of the equation to get:
x^2 = .09
take the square root of both sides of the equation to get:
x = +/- .3
substitute in your original equation to get:
when x = + .3, (3x+2)^2 = 12x + 4.81 becomes:
(3*.3+2)^2 = 12(.3)+4.81
simplify to get:
(2.9)^2 = 8.41
simplify further to get:
8.41 = 8.41
this confirms the value of x = .3 is good.
when x = - .3, (3x + 2)^2 = 12x + 4.81 becomes:
(3*-.3+2)^2 = 12(-.3)+4.81
simplify to get:
(1.1)^2 = 1.21
simplify further to get:
1.21 = 1.21
this confirms the value of x = -.3 is also good.