The answer is A. 42
Solution:
Let x= ones digit, y=tens digit
1st condition (original number) : 7(x+y)=10y + x
2nd condition (new number by reversing the digits): 18+x+y=10x+y
simplifying:
1st condition: 6x=3y
2nd condition: x=2
substituting x=2 to 6x=3y
<span>y=4</span>
The area of the circle should be 201.06
Answer:
30
Step-by-step explanation:
For a = <xa, ya> and b = <xb, yb>, the dot product is the sum of products ...
a·b = (xa)(xb) + (ya)(yb)
Substituting the given information, you have ...
a·b = 5·4 + 2·5 = 20 + 10
a·b = 30
_____
Some graphing calculators can do such math. There are also dot product calculators available on the Internet. If you have quite a few of these to calculate, you can put the appropriate formula into a spreadsheet.
Hello there. I believe it’s c
Answer:
a = 3, b = -1, c = 10
Step-by-step explanation:
Let the three numbers be a, b and c.
Equation 1: a + b + c = 12
Equation 2: a + 2b + 3c = 31
Equation 3: 9b + c = 1
Equation 2 - Equation 1:
Equation 4: b + 2c = 19
Equation 3 times by the number 2
Equation 5: 18b + 2c = 2
Equation 5 - Equation 4
17b = -17
b = -1
Substitute into Equation 4:
2c - 1 = 19
2c = 20
c = 10
Substitute into Equation 1:
a + b + c = 12
a - 1 + 10 = 12
a = 3
