Answer:

Step-by-step explanation:
We know that 
Also , 
So ,

Set up a system of equations.
X+y=6
Y-x =40
Substitution method.
Y=6-x
(6-x)-x =40
6-2x=40
-2x=34
X= -17
Plug it back into the equation.
-17+y=6
Y=33
(-17,33) is one of the possible answers.
Answer:
C) 21 girls : 9 boys
Step-by-step explanation:
You just have to compare the ratio you're given to the answers and see if the ratios from the answers match up to the ratio you were given. The reason C is the answer is because if you divide by 3 in the ration, it is the same as the ratio you were given, 7:3
Answer:
Any value greater than 19 hours.
Step-by-step explanation:
hope it helps
Answer:
6. 6x-21=33+9x 7. -15x=-5(3x+7) 8. 16x-19=113-6x 9. -19x-34=56-x 10. -6(4x+3)=6(4x-3)?
6. 6x-21 = 33 +9x
+21 + 21
6x = 54 + 9x
-9x -9x
-3x = 54
/3 /3
x = -18
7. -15x = -5(3x+7)
First multiply the -5 to the other numbers.
-15x = -15x - 35
0x = -35
7 is impossible I believe.
8. 16x-19 = 113-6x
+6 +6
22x - 19 = 113
+ 19 +19
22x = 132
/22 /22
x = 6
9. -19x - 34 = 56 - x
+19x +19x
-34 = 56 + 18x
-56 -56
-90 = 18x
/18 /18
x = -5
10. -6(4x+3) = 6[4x-3]
-24x - 18 = 24x - 18
+18 +18
-24x= 24x
x = 0, since only zero can make the equation true.