Answer:
There were 39 children at the party
Step-by-step explanation:
Here, we want to know the number of children at the party
To do this, we have to add the y-values ( frequencies of the age grades)
We have this as;
8 + 8 + 7 +10 + 6 = 39
5x + 8 - 3x = 10
First you can combine the like terms.
5x - 3x + 8 = 10
2x + 8 = 10
- 8 - 8
2x = 2

x=1
Answer:
x = ± 
Step-by-step explanation:
Given
x² - 7 = 0 ( add 7 to both sides )
x² = 7 ( take the square root of both sides )
x = ± 
Answer:
5 and 11
Step-by-step explanation:
Make equations:
x+y = 16
3x-4 = y
Substitute 3x-4 as y in x+y = 16
You get x + 3x - 4 = 16
Simplify into 4x - 4 = 16
Add 4 on both sides
you get 4x = 20
Divide each side by 4,
You get x = 5. Plug 5 back into x+y = 16
Subtract 5 from both sides, and you get y = 11