Answer: If the measures of the corresponding sides of two triangles are proportional then the triangles are similar. Likewise if the measures of two sides in one triangle are proportional to the corresponding sides in another triangle and the including angles are congruent then the triangles are similar.
Not quite sure what you mean by brackets, but you can get the solution to this equation in a few steps:
<span>(-2x - 1)</span>² <span>= 0 ... square root both sides to eliminate the squared binomial </span>√(-2x - 1)² = √0 ... simplify; the square is canceled out and the root of 0 brings you back to 0 -2x - 1 = 0 ... solve like a two-step equation -2x = 1 x = -1/2 is your x-value.