One month = 5000
Number of months before the spark plugs need to change :
15000 ÷ 5000 = 3
The sparks can last 3 months before it needs to be changed.
Number of times it need to change in a year = 12 ÷ 3 = 4
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Answer : It needs to be change 4 times a year.
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Answer:
The correct answer is 18
the correct expression is 
Step-by-step explanation:
let the number be n
therefore if he is required to multiply n by 4 and added to 6 we have

given that he did otherwise by adding 6 to n and multiply by 4 we have

Firstly we need to solve for n in equation 2

Dividing both sides by 4 we have

In order to solve for the correct answer let us input n=3 in equation 1 we have

solve for x what does x quale
x2-7x=-12
b)x=6 and x=-2
Answer:
-20
Step-by-step explanation:
It's a binomial. It's obvious hence the prefix "bi-" means 2.