Behehshehe——Hello me please

What is the value of x when x + 7 = 21?

What is the solution to the system of equation graphed belowa.(0,-4)b.(2,5),1),-3)

Afactory buys 10% of its components from suppliers b and the rest from supplier c. it is known that 6% of the components it buys are faulty. of the components brought from suppliers a,9% are faulty and of the components bought from suppliers b, 3% are faulty. find the percentage of components bought from supplier c that are faulty.