(Multiply all by 3 )
7x+x=3+5x
8x=3+5x
3x=3
x=1
Answer: 3, 5, 7
Step-by-step explanation:
There is a "trick" to determine divisibility by 3: if the sum of the digits is divisible by 3, the number is divisible by 3.
3 + 1 + 5 = 9 which is a multiple of 3, so 315 is divisible by 3.
It works for 9 also. since the sum of the digits is 9, 315 is divisible by 9.
Divisibility by 5: any number that has the units digit 5 or 0 is divisible by 5.
For 7, I just tried it 315÷7= 45
Only even numbers are divisible by 2.
If a 3-digit number is divisible by 11, the middle digit will be the sum of the first and last digits. (That is not the case for 315) But 385 is divisible by 11, also 495, 253, and many others you can try for fun.
Negative integer.
-761 + 317= -444
Plug the answer in:
-761 - (-444)
= -317
Reminder: when multiplying two negatives, you get a positive.
Answer:
x = - 5
Step-by-step explanation:
Given
5x + 7 = 2x - 8 ( subtract 2x from both sides )
3x + 7 = - 8 ( subtract 7 from both sides )
3x = - 15 ( divide both sides by 3 )
x = - 5
