Answer:

Step-by-step explanation:
The additive number of any number is the number when added to the number gives a result of zero.
So, if we add 10 to -10 we get a result of zero.
=> -10+10
=> Zero
Round down to 10. 13 goes to 10.
Answer:
x = 11, y = 8
Step-by-step explanation:
ΔABC and ΔFDE are congruent by the postulate SSS
Equate the congruent sides in the 2 triangles
BC = ED, that is
x + 3 = 14 ( subtract 3 from both sides )
x = 11
-------------------------------------
DF = AB, that is
x - y = 3 ← substitute x = 11
11 - y = 3 ( subtract 11 from both sides )
- y = 3 - 11 = - 8 ( multiply both sides by - 1 )
y = 8
4 = 2 * 2
Multiplying by 2 is the same a doubling.
Since 4 is 2 * 2, to multiply a number by 4, double the number twice.
Example:
What is 4 * 100?
Double 100 to get 200.
Double 200 to get 400.
Therefore, 4 * 100 = 400.
By doubling twice, we do the same as multiplying by 4.
Answer:
x = 45/7
Step-by-step explanation:

Here, you can more easily see what the fractions look like.
In order to cross-multiply, you have to multiply 5 with 9, and 7 with x.
45 = 7x
Then, you isolate x by dividing 7 on both sides:
45/7 = x
Hope I helped :)