book Maths Puzzle Numerical Ability

what is y=-3x-1 and i have to graph it

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book Other Question

This one is addition instead of substitution. I couldn't find the right place to put it. This one is just as confusing to me.

1/3*x - 1/2*y = 5/6
1/2*x - 2/5*y = 9/10

Thank is v(v-3) = v^2 + 6 a quadratic equation and if so what is the solution?