Answer: 7 × ( 3^n - 1 )
Step-by-step explanation:
This is a geometric progression which has its nth term to be
Tn = ar^n- 1. Now from the question given, the sequence are 7, 21, 63, 189. This is an example of a finite sequence, To find the common ratio, you divide the second term by the first term. So
r = 21/7
= 3. , a = 7
Now to find the nth term put the values in the formula above.
Tn =ar^n-1
= 7(3)^n - 1)
= 7 × ( 3^n - 1 ).
Note, it is not 21^n - 1.
Answer:
2
Step-by-step explanation:
Look here!
Answer:
= 440 ft
Step-by-step explanation:
The perimeter of a rectangle is found by adding up all the sides. We use the formula
P =2(l+w)
where l is the length and w is the width
The length is 140 and the width is 80
P = 2(140+80)
= 2(220)
= 440 ft
Answer: you have to use d=rt to figure it out. that is distance equals to rate times time
Step-by-step explanation:
hope that helps
Answer: 14x^2-93xy+60y^2 Hope that helps!
Step-by-step explanation:
1. Expand by distributing terms
(20x-12y)(x-4y)-(3x-4y)(2x+3y)
2. Use the Foil method:(a+b)(c+d)= ac+ad+bc+bd
20x^2-80xy-12yx+48y^2-(3x-4y)(2x+3y)
3. Use the Foil method : (a+b)(c+d)= ac+ad+bc+bd
20x^2-80xy-12yx+48y^2-(6x^2+9xy-8yx-12y^2)
4. Remove parentheses 20x^2-80xy-12yx+48y^2-6x^2-9xy+ 8yx+12y^2
5. Collect like terms (20x^2-6x^2)+(-80xy-12xy-9xy+8xy)+(48y^2+12y^2)
6. Simplify.
And your answer would be 14x^2-93xy+60y^2
