Question

25x²+90xy+81y²,when x= -9,y=5 find the value of following expressions​

Answer 1

Answer:

= 8095

Step-by-step explanation:

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Answer 2

Answer:

(5x - 9y)2

Step-by-step explanation:

Step 1:

((25 • (x2)) -  90xy) +  34y2

Step 2:

(52x2 -  90xy) +  34y2

Step 3:

3.1    Factoring    25x2 - 90xy + 81y2  

Try to factor this multi-variable trinomial using trial and error  

Found a factorization  :  (5x - 9y)•(5x - 9y)

Step 4:

3.2    25x2  -90xy  +81y2  is a perfect square  

It factors into  (5x-9y)•(5x-9y)

which is another way of writing  (5x-9y)2

How to recognize a perfect square trinomial:  

• It has three terms  

• Two of its terms are perfect squares themselves  

• The remaining term is twice the product of the square roots of the other two terms

FINAL ANSWER:

(5x - 9y)2