Question

URGENTE
a) x+2y=5
x+3y=8

b)3x+yy=-5
x-2y=5

Answer 1

a) $\left \{ {{x=5-2y} \atop {x+3y=8}} \right. \\ \\ 5-2y+3y=8 \\ y=3 \\ \\ x=5-2.3 \\ x=-1$

b) $\left \{ {{3x+y=-5} \atop {x=5+2y}} \right. \\ \\ 3(5+2y)+y=-5 \\ 15+6y+y=-5 \\ 7y=-20 \\ y= \frac{-20}{7} \\ \\ x=5+2. (\frac{-20}{7} ) \\ x=5- \frac{-40}{7} \\ x=35-40 \\ x=-5$