Question

What would be the first step to slove the system of equations 2x-9y=6 and 4x-3y=-7

Answer 1

If there are choices, then you  need to choose the correct choice, but if there are no choices, then one correct answer is to multiply the first equation by -2 and add it to the second equation to eliminate x and solve for y.

Answer 2

The first step varies depends on what method you want to use to solve the system of equations. 
If it is me, my first step would be either doubling the first equation so the coefficients of x in both equations equal to each other, or tripling the second equation so the coefficient of y in both equations is set equal.

2x-9y=6
4x-3y=-7

3(second euation) =12x-9y=-7

second equation subtract the first equation
10x=-13
x=-13/10

Then we can plug x in any of the two original equations and solve for y which i got to be -19/15