Answer:
See below.
Step-by-step explanation:
I will assume that 3n is the last term.
First let n = k, then:
Sum ( k terms) = 7k^2 + 3k
Now, the sum of k+1 terms = 7k^2 + 3k + (k+1) th term
= 7k^2 + 3k + 14(k + 1) - 4
= 7k^2 + 17k + 10
Now 7(k + 1)^2 = 7k^2 +14 k + 7 so
7k^2 + 17k + 10
= 7(k + 1)^2 + 3k + 3
= 7(k + 1)^2 + 3(k + 1)
Which is the formula for the Sum of k terms with the k replaced by k + 1.
Therefore we can say if the sum formula is true for k terms then it is also true for (k + 1) terms.
But the formula is true for 1 term because 7(1)^2 + 3(1) = 10 .
So it must also be true for all subsequent( 2,3 etc) terms.
This completes the proof.
Answer:
x = -5
Step-by-step explanation:
If g(x)= 3x - 12, and g(x)= -27 then -27 = 3x -12
Solve for x
-27 = 3x -12, add 12 to both sides
-27+12 = 3x, add -27+12
-15 = 3x, divide both sides by 3
-5 = x
Answer:
x=−2 and y=−1
Step-by-step explanation:
<u>Problem:</u>
Solve y=x2;y=−x−3
<u>Steps:</u>
I will solve your system by substitution.
y=1/2x;y=−x−3
Step: Solve y= 1/2x for y:
Step: Substitute 1/2 x for y in y=−x−3:
y=−x−3
1/2x= =−x−3
1/2x+x=−x−3+x(Add x to both sides)
3/2x = -3
3/2x/3/2 = -3/3/2 (Divide both sides by 3/2)
x=−2
Step: Substitute −2 for x in y=1/2x:
y=1/2x
y=1/2(-2)
y=−1(Simplify both sides of the equation)
<u>Answer:</u>
x=−2 and y=−1
Answer:
c=8
Step-by-step explanation:
Simplifying
3c + -15 = 17 + -1c
Reorder the terms:
-15 + 3c = 17 + -1c
Solving
-15 + 3c = 17 + -1c
Solving for variable 'c'.
Move all terms containing c to the left, all other terms to the right.
Add 'c' to each side of the equation.
-15 + 3c + c = 17 + -1c + c
Combine like terms: 3c + c = 4c
-15 + 4c = 17 + -1c + c
Combine like terms: -1c + c = 0
-15 + 4c = 17 + 0
-15 + 4c = 17
Add '15' to each side of the equation.
-15 + 15 + 4c = 17 + 15
Combine like terms: -15 + 15 = 0
0 + 4c = 17 + 15
4c = 17 + 15
Combine like terms: 17 + 15 = 32
4c = 32
Divide each side by '4'.
c = 8
Simplifying
c = 8
