9. Simran had some ₹2 and ₹ 5 coins.She exchanged them for ₹ 10 coins. If the number of ₹ 5 coins is one less than the number of
1 answer:
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
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Answer:
1. x = 12
2. 3∛4 feet.
Step-by-step explanation:
1. We are given the equation of x as and we have to find the extraneous solution of the equation.
Now, ............. (1)
⇒
Squaring both sides we get,
⇒ x - 3 = 81 - 18x + x²
⇒ x² - 19x + 84 = 0
⇒ x² - 12x - 7x + 84 = 0
⇒ (x - 12)(x - 7) = 0
⇒ x = 12 or 7.
Now, putting x = 12 in the equation (1) we get,
Again, putting x = 7 in the equation (1) we get,
Therefore, x = 12 is an extraneous solution of this equation. (Answer)
2. The volume of a cube with side lengths a ft. is given to be 108 ft³.
So, a³ = 108
⇒ a = 3∛4 feet.
Therefore, the length of the sides of the cube are each 3∛4 feet. (Answer)