Answer:
the sum of four consecutive, odd whole numbers is 48
Step-by-step explanation:
First thing to do is to solve each of these for y. The first one is y=-4x-3; the second one is y=4x-21; the third one is y=4x+21; the fourth one is y=-4x+3. From that you can tell the positive slopes are found in the second and third equations. Those are the ones we will test now for the point (3, -9). y=-9 and x=3, so let's fill in accordingly. The second equation filled in is -9=4(3)-21. Does the left side equal the right when we do the math? -9=12-21 and -9=-9. So the second one works. Just for the sake of completion, let's do the same with the third: -9=4(3)+21. Does -9=12+21? Of course it doesn't. Our equation is the second one above, y+9=4(x-3).
<h3>
Answer: True</h3>
Explanation:
Technically you could isolate any variable you wanted, from either equation. However, convention is to pick the variable in which isolating it is easiest, and most efficient.
The key thing to look for is if there's a coefficient of 1. This is found in the second equation for the y term. Think of -4x+y = -13 as -4x+1y = -13. Due to the coefficient of 1, when solving for y we won't involve messy fractions.
If you were to solve for y, then you'd get y = 4x-13, which is then plugged in (aka substituted) into the first equation. That allows you to solve for x. Once you know x, you can determine y.
Answer: C. None of the above
Step-by-step explanation:
