Answer:
6
Step-by-step explanation:
Answer:
L=10cm , W=30cm
Step-by-step explanation:
First use the given that W=10+2*L
Use P=2W+2L=80, substitute W in the perimeter formula
2(10+2L)+2L=80 and solve for L,
20+4L+2L=80 isolate variable L and combine like terms,
6L=80-20,
L=10, so W=10+2*10=10+20=30
Answer:

Step-by-step explanation:
{у = 3х - 12
{4х + 6у = −6
4x + 6[3x - 12] = −6
4x + 18x - 72 = −6
−6 = −72 + 22x
+72 + 72
___________
66 = 22x
__ ___
22 22
[Plug this back into both equations above to get the y-coordinate of −3]; 
I am joyous to assist you anytime.
I Believe Its 9
9 * 3 = 27
9 * 4 = 36
Or
27 / 9 = 3
36 / 9 = 4
x+19= 26
x+19-19= 26-19
x= 7
Check answer by using substitution method
x+19= 26
7+19= 26
26= 26
Answer is x= 7 (D.)