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)
Answer:
y = - 9
Step-by-step explanation:
Substitute in -1 for x
8(-1) - 2y = 10
-8 - 2y = 10
Subtract -8 from both sides
-8 - (-8) cancels out to 0
10 - (-8) = 18
We are left with:
-2y = 18
Divide by -2 on both sides.
-2y/-2 = y
18/-2 = -9
y = -9
The correct answer is 2 3/4