Answer:
There are <u>35 boys</u> in the class.
Step-by-step explanation:
Girls to Boys ratio = 3:7
Total number of students in class = 50
Let total number of girls be '3x' and total number of boys be '7x'
Total number of girls + Total number of boys = Total number of students
3x + 7x = 50
10x = 50
x = 50/10
x = 5
Total number of girls = 3 × 5 = 15
Total number of boys = 7 × 5 = 35
The answer to the question is B. 8
Answer: The distance between the points (-6,7) and (-1,-5) is 13 units.
Solution:
P1=(-6,7)=(x1,y1)→x1=-6, y1=7
P2=(-1,-5)=(x2,y2)→x2=-1,y2=-5
Distance between points P1 and P2: d=?
d=sqrt [ (x2-x1)^2 + (y2-y1)^2 ]
Replacing the knwon values:
d=sqrt [ (-1-(-6))^2 + (-5-7)^2 ]
d=sqrt [ (-1+6)^2 + (-12)^2 ]
d=sqrt [ (5)^2 + 144 ]
d=sqrt [ 25 + 144 ]
d=sqrt [ 169 ]
d=13
Answer:


Step-by-step explanation:
Given

Required
(a) Make a perfect square trinomial
(b) Write as binomial square
Solving (a)
Let the missing part of the expression be k;
This gives

To solve for k, we need to square half the coefficient of n;
i.e. Since the coefficient of n is
, then



Hence;
= 
Solving (b)

Expand 

Factorize



Hence:
= 

because

is a set with the element 0, so it's not the empty set, while

is the empty set.