Question

Find the value of the expression 16x² + 56xy + 49y2,
when x = 5 and y = 7.​

Answer 1

Answer:

3430

Step-by-step explanation:

x^2=49 and xy=35

16 * 49 +  56*35 + 19*14 == 3430

Answer 2

Answer:

(4x-7y)^2

Step-by-step explanation:

Rewrite  

16 x^ 2  as  ( 4 x ) ^2 .

( 4 x ) ^2 − 56 x y + 49 y ^2

 Rewrite  

49 y ^2  as  ( 7 y ) ^2 .

( 4 x ) ^2 − 56 x y + ( 7 y ) ^2

Check the middle term by multiplying  2 a b  and compare this result with the middle term in the original expression.

2 a b = 2 ⋅ ( 4 x ) ⋅ ( − 7 y )

Simplify.

2 a b = − 56 x y

Factor using the perfect square trinomial rule  a ^2 − 2 a b + b ^2 = ( a − b ) ^2 , where a = 4 x  and  b = − 7 y .

( 4 x − 7 y ) ^2.

hope it helps........