Answer:
9y(2x - 1)(x - 2y)(x + 2y)
Step-by-step explanation:
Given
18x³y - 9x²y - 72xy³ + 36y³ ← factor out 9y from each term
= 9y(2x³ - x² - 8xy² + 4y²)
Factor the first/second and third/fourth term in the parenthesis
= 9y( x²(2x - 1) - 4y²(2x - 1)) ← factor out (2x - 1) from each term
= 9y(2x - 1)(x² - 4y²)
x² - 4y² is a difference of squares and factors in general as
a² - b² = (a - b)(a + b), thus
x² - 4y²
= x² - (2y)² = (x - 2y)(x + 2y), hence
18x³y - 9x²y + 72xy³ + 36y³
= 9y(2x - 1)(x - 2y)(x + 2y) ← in factored form
3. A
2. C
Idk if you should repost this with a better pic though
The general formula for geometric series is tn = a×rⁿ⁻¹. In this question, a (or a1) is 3, and r is 1.1, therefore the first ten terms would be 3×1.1⁰ (3) , 3×1.1¹ (3.3), 3×1.1² (3.63) and so on up until you get to 3×1.1⁹ or 7.07.
D
is certainly wrong. You could extend the length of AD as far as you want and the two triangles (ABD and ACD) would still be congruent.
C
is wrong as well. The triangles might be similar, but they are more. They are congruent.
B
You don't have to prove that. It is given on the way the diagram is marked.
A
A is your answer. The two triangles are congruent by SAS
