# What value should be added to each side of x^2+4x=-6 to complete the square? Would it be -4 that needs to be added to each side? Thanks much, Tricia

*print*Print*list*Cite

### 1 Answer

For x^2+4x=-6, the square on the left needs to be completed.

Use the relation (a+b)^2 = a^2 + b^2 + 2*a*b

x^2+4x=-6

=> x^2 + 2*2*x = -6

=> x^2 + 2*2*x + 2^2 = -6 + 2^2

=> (x + 2)^2 = -6 +4

=> (x + 2)^2 = -2

**The number 4 has to be added to both the sides to complete the square on the left.**