Question

A student concluded that the solution to the equation sqrt2x+1 +3=0 is x=4. Do you agree? Why or why not?

Answer 1

I do not agree with the student because there is no real solution.

Solving the equation only gives possible solutions, but you must check them in the original equation.

Checking the solution in the original equation shows that 4 is an extraneous solution.

Explanation:

sample answer edg 2020

Answer 2

Just put 4 as x in the equation and solve it. The new equation is:

sqrt(2*4)+1+3 = 0

Now we can solve it.

sqrt(2*4) becomes sqrt8:

sqrt8+1+3=0. -------> sqrt8+4=0

The sqrt of 8 is about 2.83.. so 2.83+4 is:

6.83

So we have 6.83 as the answer

but 6.83 does not equal 0 so x cannot equal 4