Answer
a. yes
b. no
Work Step by Step
To find out if an ordered pair is a solution you need to insert the values of the variables into the equation. If the answer of the system is true, the pair is a solution, if not it isn't.
a. $3\times3-4=5<=>5=5$
$3+2\times4=11<=>11=11$
b. $3\times0--5=5<=>5=5$
$0+2\times-5=11<=>-10\ne11$$
