Answer:
You can use substitution, elimination, or graphing.
Step-by-step explanation:
So what I would do, is using elimination because you have two variables that are the same, what I mean is that you have two -3y's, So, take one equation, lets do the top one, and multiple the whole thing, yes, the WHOLE THING meaning both sides by -1. This will give you -6x+3y= -12. The negative turns to positive because you multiply the -3y by -1. Notice how you have a +3y in the top equation now and a -3y in the bottom one. This is why the method is called elimination, you can cross out the +3y and -3y and combine both equations. You now have -2x=12. Divide both sides by -2, x=-6. Plug -6 in the first equation, you get 6(-6)-3y=12 which goes to -36-3y=12. Add 36 on both sides, you get -3y=48. Divide both sides by -3, you get y=-16. Oh yeh, plug y into one of the equations and solve for x, i forgot to say that.
Answer:
D: x = -18
Step-by-step explanation:
A good way to solve this it to input all options until you find the one that fits for both options.
Option A :
15 + 6 / 15 - 3 = 21 / 12 or 7/4
So this one doesn't work.
Option B :
10 + 6 / 10 - 3 = 16 / 7
So this one also doesn't work.
Option C:
3 + 6 / 3 - 3 = 9 / 0 which is 0 by the laws of dividing by zero.
This one also doesn't work leaving only one option.
Option D:
-18 + 6 / -18 - 3 = -12 / -21 or 4 / 7
And by solving we can find out we did our work correctly and get our answer.
first solve for the perimeter of the rectangle
2w + 2l = 42
since the length of the rectangle is twice as long as the length and width of the square
2w = l
solve using substitution
2w + 2(2w) = 42
2w + 4w = 42
6w = 42
w = 7
are is length x width. a square has the same length and width
7 x 7 = 49
the area of one square is 49
First day : 30+20y
Second day : 85 + 17y
Total: 30 + 20y + 85 + 17y This is the not simplified version.
37y+115 This is the simplified version.
10÷2=5 5×2=10 10+20=30 30-5=25.