It's a horizontal line at some value of y. Solve it for y.
70-10y=0
Subtract 70 from both sides.
-10y=-70
Divide both sides by -10.
y = 7
Draw it on the graph.
If you need help understanding math so you can solve these problems yourself, then one on one online tutoring is the answer ($30/hr). If you need faster solutions with guaranteed detailed answers, then go with personal problem solving ($3.50-$5.50 per problem). Contact me at fcabanski@hotmail.com