Two lines, r and m, are represented by the following equations:
line r: 2x + 2y = 18
line m: x + y = 9
which statement is true about the solution to the set of equations?
it is (18, 9).
it is (9, 18).
there are infinitely many solutions.
there is no solution. (i know it's not this one)

Girardo is using the model below to solve the equation . girardo uses the following steps: step 1 add 4 negative x-tiles to both sides step 2 add 1 negative unit tile to both sides step 3 the solution is which step could be adjusted so that gerardo's final step results in a positive x-value? in step 1, he should have added 4 positive x-tiles to both sides. in step 1, he should have added 3 negative x-tiles to both sides. in step 2, he should have added 4 negative unit tiles to both sides. in step 2, he should have added 1 positive unit tile to both sides.