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


Answer:
9 inches
Step-by-step explanation:
Do the question algebraically, represented by this equation:
let x be the shorter piece
x + (x + 8) = 26 (longer piece is 8 units longer)
Remove brackets
x + x + 8 = 26 Combine like terms
2x + 8 = 26 Start isolating "x"
2x + 8 - 8 = 26 - 8 Subtract 8 from both sides
2x = 18
2x/2 = 18/2 Divide both sides by 2
x = 9 shorter piece
The shorter piece would be 9 inches.
If you needed the longer piece too:
longer piece = x + 8
x + 8
= 9 + 8
= 17
The longer piece would be 17 inches.
Check your answer:
Longer + Shorter = 26 Substitute the lengths
17 + 9 = 26 Add
26 = 26 same number
LS = RS left side equals right side
The answer is correct.
Answer:
135°
Step-by-step explanation:
The sum of interior angles in this rectangle is equal to 720
Two of the angles are right (has 90°)
so 4x + 180 = 720 subtract 180 from both sides
4x = 540 divide both sides by 4
x = 135°
3 sides of square is 3*12=36 cm
perimeter for the full circle is 2 * pi * radius
which is =2 * 22/7 * 12 =75.43 cm
so 360° =75.43 cm
for 150° = 75.43/360 *150 =31.43
all together =36 +31.43 =67.43 cm