Question

Find the value of 81 - 4x² for x = 4​ please help me ☹︎ ​

Answer 1

81

−

4

x

2

Rewrite

81

as

9

2

.

9

2

−

4

x

2

Rewrite

4

x

2

as

(

2

x

)

2

.

9

2

−

(

2

x

)

2

Since both terms are perfect squares, factor using the difference of squares formula,

a

2

−

b

2

=

(

a

+

b

)

(

a

−

b

)

where

a

=

9

and

b

=

2

x

.

(

9

+

2

x

)

(

9

−

(

2

x

)

)

Multiply

2

by

−

1

.

(

9

+

2

x

)

(

9

−

2

x

)

Answer 2

Step-by-step explanation:

the value of the given equation is

17

✌✌❤hope it helps u thank u❤❤✌