Question 18120
To prove this, you need only to substitute the x and y-values of the given point into both equations and see if they satisfy them both.

If both equations are satisfied by the coordinates of the given point ( 4, 3), then the given point is a solution to the system; if they aren't, then it isn't.

{{{x + 2y = 10}}}
{{{4 + 2(3) = 4 + 6}}} = 10  This one is ok.

{{{3x + 5y = 3}}}
{{{3(4) + 5(3) = 12 + 15}}} = 27 This is not = 3, so the given point (4, 3) does not satisfy the system of equations.