Answer:


Step-by-step explanation:
Given


Solving (a): T7
Substitute 7 for n in 


Calculate S7 and S6



So:


Solving (b): Tn

Where 
Calculate
We have:

Open brackets



So:



Collect Like Terms


<span><span><span>2x</span>+3</span>=<span><span>
[email protected]</span><span>x=6</span></span></span><span><span><span><span>(2)</span><span>(6)</span></span>+3</span>=15</span><span><span>15=</span><span>15</span></span>
Answer: B) -48
Step-by-step explanation:
If the system of two linear equations
has infinitely many solutions , then

For the given system of linear equations : 
We , will have

The value of 
Hence, the value of rs is -48.
Thus , the correct option is B) -48.
Answer:
39 liters
Step-by-step explanation:
6.5×6=39
so 39 litres
Step-by-step explanation:
4/5 is the simplified fraction for 48/60.