SOLUTION: How do I solve the follwoing system of equations? y = {{{ sqrt (x) }}}+ 4 y = 2x + 1 Can you provide a detailed answer showing all of the steps?

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Question 188800: How do I solve the follwoing system of equations?
y = + 4
y = 2x + 1


Can you provide a detailed answer showing all of the steps?

Found 2 solutions by jim_thompson5910, Alan3354:
Answer by jim_thompson5910(35256)   (Show Source): You can put this solution on YOUR website!
Start with the first equation.


Plug in


Subtract 4 from both sides.


Combine like terms.


Square both sides


FOIL


Subtract x from both sides.


Combine like terms.


Notice we have a quadratic equation in the form of where , , and


Let's use the quadratic formula to solve for x


Start with the quadratic formula


Plug in , , and


Negate to get .


Square to get .


Multiply to get


Subtract from to get


Multiply and to get .


Take the square root of to get .


or Break up the expression.


or Combine like terms.


or Simplify.


So the possible answers for "x" are or


However, if you plug in into the equation , you'll find a contradiction. So this is an extraneous solution (ie we must ignore this value).


So the only solution for "x" is


Now plug in into to find "y"



Answer by Alan3354(69443)   (Show Source): You can put this solution on YOUR website!
How do I solve the follwoing system of equations?
y = + 4
y = 2x + 1
------------
There's more than one way, but since both right sides = y, I'd set them equal to each other.
2x+1 = sqrt(x) + 4
sqrt(x) = 2x-3
x = 4x^2 - 12x + 9
4x^2 - 13x - 9 = 0
Solved by pluggable solver: SOLVE quadratic equation (work shown, graph etc)
Quadratic equation (in our case ) has the following solutons:



For these solutions to exist, the discriminant should not be a negative number.

First, we need to compute the discriminant : .

Discriminant d=313 is greater than zero. That means that there are two solutions: .




Quadratic expression can be factored:

Again, the answer is: 3.83647575161927, -0.586475751619266. Here's your graph:



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