Answer:
Step-by-step explanation:
a+b+c=0, a+b=-c,a+c=-b, b+c=-a
(a+b+c)^3=(a+b+c)^2*(a+b+c)=(a^2+b^2+c^2+2ab+2ac+2bc)*(a+b+c)=
a^3+ab^2+ac^2+2a^2b+2a^2c+2abc+a^2b+b^3+bc^2+2ab^2+2abc+2b^2c+a^2c+b^2c+c^3+2abc+2ac^2+2bc^2=a^3+b^3+c^3+3a^2b+3a^2c+3ac^2+3ab^2+3bc^2+3b^2c+6abc=
a^3+b^3+c^3+3a^2*(b+c)+3c^2(a+b)+3b^2(a+c)+6abc=
a^3+b^3+c^3+3a^2*(-a)+3c^2*(-c)+3b^2*(-b)+6abc=
a^3+b^3+c^3-3a^3-3c^3-3b^3+6abc=
6abc-2a^3-2b^3-2c^3=2(3abc-a^3-b^3-c^3)=
2*[3abc-(a^3+b^3+c^3)]=0
so 3abc-(a^3+b^3+c^3)=0
so a^3+b^3+c^3=3abc
Answer:
30
Step-by-step explanation:
1. x + 40 = 3x - 20
2. 40 = 2x - 20
3. 60 = 2x
4. 30 = x
Answer:
20, 4
Step-by-step explanation:
Let's assume total number of students registered is n
Last week n/4 people are absent
so people present are n - n/4 = <u>3n/4</u>
Today after return of Jen 1/5 n are absent
so people present are n - n/5 = 4n/5
which is also equal to last week present people + 1 (Jen)
= 3n/4 + 1
= (3n + 4) / 4
so (3n + 4) / 4 = 4n/5
=> 3n + 4 = 4n/5 * 4
=> (3n + 4) * 5 = 16n
=> 15n + 20 = 16n
=> 20 = n
=> n = 20
So total students registered for class is 20
today no of people absent = n/5 = 20/5 = 4
Answer:
x+5x=84
6x=84
6x/6=84/6
x=14
so therefore
14+5(14)
14+70
The numbers are 14 and 70
Answer:
5
Step-by-step explanation:
x = 2 >>> (Multiply by 10) >>> y = 20
x = ? >>> (Multiply by 10) >>> y = 50
50 ÷ 10 = 5
x = 5 when y is 50
