Answer:
x²(9x– 11)(9x + 11)
Step-by-step explanation:
81x⁴ – 121x²
The expression can be factorised as follow:
81x⁴ – 121x²
x² is common to both term. Thus:
81x⁴ – 121x² = x²(81x² – 121)
Recall:
81 = 9²
121 = 11²
Therefore,
x²(81x² – 121) = x²(9²x² – 11²)
= x²[(9x)² – 11²]
Difference of two squares
x²(9x– 11)(9x + 11)
Therefore,
81x⁴ – 121x² = x²(9x– 11)(9x + 11)
Third length =
12-7 = 5
12+7 = 19
Third length can be only in this range
5Means the third length must be greater than 5 and less than 19.
Hope this helps!
Answer:
Step-by-step explanation:
2(l+b)=16
Also it is given that l=2b+2
2(2b+2+b)=16
3b+2=8
b=2metre
l=2(2)+2
l=6metre
7.
If c = 16
that means the equation is
16 - 9
which is 7
so 7
