# How do you solve #x^2 + 2x = 3# by completing the square?

##### 1 Answer

Because the sign of the x term is positive, we use the pattern:

#### Explanation:

Given:

Add

Please observe that the left side of equation [2] now resembles the right side of equation [1]. This means that we can set the middle term of equation [1] equal to the middle term of equation [2], to find the value of "a":

Substitute 1 for "a" in equation [2]:

Because we have completed the square, the left side of equation [3] collapses into a square with

Perform the square root operation on both sides:

Subtract 1 from both sides: