En una plaza circular de radio (3x + 4)2 se instala en su centro una fuente también de forma circular de radio (2x + 1)2 . Calcule el área que queda libre después de instalada la fuente en la plaza. ayuda porfa

How many solutions does the nonlinear system of equations graphed bellow have?

Precalculus question, image attached.

Statements reasons 1. ab ? cd; ad ? bc 1. given 2. ac ? ac 2. reflexive property 3. ? adc ? ? cba 3. ? 4. ? dac ? ? bca; ? acd ? ? cab 4. cpctc 5. ? dac and ? bca are alt. int. ? s; ? acd and ? cab are alt. int. ? s 5. definition of alternate interior angles 6. ab ? cd; ad ? bc 6. converse of the alternate interior angles theorem 7. abcd is a parallelogram 7. definition of parallelogram what is the missing reason in step 3?