Answer:
-77
Step-by-step explanation:
Simply plug in:
Because the "-" sign is outside the parentheses, you would distribute.
It would then be: -3-4. *positive and negative=negative, negative and negative=positive. -3-4=-7. It would then be: (-7) · ((3-(-4)(2))
(-4)(2)=-8. →(3-(-8))=(3+8)=11. The equation would then be: (-7) · (11)= -77
Answer:
<em>Cathy was born in 1980 and she was 18 years old in 1998</em>
Step-by-step explanation:
<u>Equations</u>
This is a special type of equations where all the unknowns must be integers and limited to a range [0,9] because they are the digits of a number.
Let's say Cathy was born in the year x formed by the ordered digits abcd. A number expressed by its digits can be calculated as
In 1998, Cathy's age was
And it must be equal to the sum of the four digits
Rearranging
We are sure a=1, b=9 because Cathy's age is limited to having been born in the same century and millennium. Thus
Operating
If now we try some values for c we notice there is only one possible valid combination, since c and d must be integers in the range [0,9]
c=8, d=0
Thus, Cathy was born in 1980 and she was 18 years old in 1998. Note that 1+9+8+0=18