Efficiency Formula for energy on a green chalkboard. Education. Science. Formula. Vector illustration.
Palabras clave
blackboard,
board,
chalk,
school,
blackboard,
education,
concept,
word,
green,
cloud,
frame,
blank,
classroom,
class,
black,
write,
wood,
illustration,
vector,
instructing,
empty,
business,
back,
eraser,
learning
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