Answer:
Step-by-step explanation:
Rule Example
+(+) Two like signs become a positive sign 3+(+2) = 3 + 2 = 5
−(−) 6−(−3) = 6 + 3 = 9
+(−) Two unlike signs become a negative sign 7+(−2) = 7 − 2 = 5
−(+) 8−(+2) = 8 − 2 = 6
Answer:
S=-2
Step-by-step explanation:
Answer:
I'm not so sure but i guess it's option D y=5x-3
the question said that the number of box of nails are purchased depending on how many houses they planned to build. so for knowing the boxes of nails they need to purchase they need to subtract the boxes which were left and the boxes we need now
Answer:
Step-by-step explanation:
Let x be the number of 2 coins and y be the number of 5 coins. Let z be the number of 10 coins she exchanged. Then, we have the first equation

Since she has one 5 coin less than 2 coins, then y=x-1. So we get the equation
which is equivalent to
If we add 5 on both sides and factor out on the right by 5 we get

We can solve for x and get
Since x represents the number of 2 coins, we must have that x is an integer. That is, we cannot have, for example 1.5 2 coins. Since 7 doesn't divide 5, we must have that 7 divides 2z+1. That is, the value of z is such that the number 2z+1 is multiple of 7. That is 2z+1 = 7p where p is an integer.
If that is the case, then
x = 5p, then y = 5p-1. By having 2z+1 = 7p, we are forcing that p is an odd integer, so we have infinite solutions. For each value of p that is an odd integer, then x=5p and y=5p-1 is a solution to the problem