A student determined that the ordered pair \( (3,-5) \) is a solution of the following system. \[ \begin{array}{r}4 x+y=4 \\ x+y=-2\end{array} \] His reasoning was that the ordered pair satisfies the second equation \( x+y=-2 \), since \( 3+(-5)=-2 \). What went wrong?

2) En un aula de ticeo Colombia joven hay un total de 27 alumnos, habiendo el doble de chicas que de chicos. ¿Cuántos chicos y chicas hay en el, aula? a) 18 chicos y 9 chicas. b) 9 chicos y 18 chicas. c) 18 chicas y 9 chicos. d) 15 chicos y 12 chicas.

Find the product : \( \left(-7 a^{4}\right. \) b) \( \left(4 a^{2} b^{5} c^{2}\right) \) \( \begin{array}{ll}\text { a) }-28 a^{6} b^{6} c^{2} & \text { b) } 28 a^{6} b^{5} c^{2} \\ \text { c) } 28 a^{6} b^{6} c^{2} & \text { d) }-28 a^{4} b c^{2}\end{array} \)

5o. \( x^{2}-y^{2}+2 x+1 \)

Divide and state the quotient in simplest form. \( \frac{72 y}{y^{2}-9} \div \frac{48 y}{y^{2}-6 y+9} \) \( \frac{3\left(y^{2}-6 y+9\right)}{2\left(y^{2}-9\right)} \) \( \frac{2 y+6}{3 y-9} \) \( \frac{3}{2} \) \( \frac{3 y-9}{2 y+6} \)

sif \( a=1, b=2 \) and \( c=-1 \) \( 6 a^{2} c-4 b^{2} c-3 c^{2} a-b c-c^{2}-2 b^{2} c-a^{2} c \)