Two lines, a and b, are represented by the equations given below: line a: x + y = 6 line b: x + y = 4 which statement is true about the solution to the set of equations? there are infinitely many solutions. there is no solution. it is (6, 4). it is (4, 6).

If the lines cross, there is a solution , which means that there is a y and x value which satisfies both equations. 
since both the equations start with x+y they shoulddd have the same answer if they had crossed. we can tell straight away these lines do not cross because 6=/=4 6 doesnt equal 4. therefore no solution. 
TIP: for the future, if they had crossed, you can use simultaneous equations to find x and y to see if they work in each equation and find a solution ( since they are straight lines there will only be 1 solution, unless they are literally the same line in which case then then they are ALWAYS on top of each other and always have the same values)