Respuesta :

Answer:

c=400

Step-by-step explanation:

Use the perfect square formula:

ax^2+bx+c=0

x^2-40x+c=0

bring c to the other side

x^2-40x+___=-c

divide -40 by 2 then square it; 400

add 400 to each side

c=400

(x-20)(x-20)
Answer:
C=400
Step-by-step explanation:
Use the perfect square formula:
ax ^2+bx+c=0
x^2-40x+C=0
bring c to the other side
x^2-40x+
-C
divide -40 by 2 then square it; 400
add 400 to each side
<=400
(x-20) (x-20)