Answer:
Step-by-step explanation:
1) -5 +3 = -2
When two numbers are in different sign, subtract and the result will have the bigger numbers sign. The bigger number is 5. so the result is (-2)
2) -7 - 2 = -9
When two numbers have same sign, add and the result will have the common sign
3) 122 * (-9) = - 1098
4) -6 ÷ (3/4)
= -8
45 and 45 because they are equal and add up to 90 degrees
Answer:Alden is 13 years old
Step-by-step explanation
Let x represent Alden's age.
Let y represent the age of his sister.
Let z represent the age of his second sister.
His sister is 5 years older than he is and 3 times as old as his second sister. This means that
y = x + 5
y = 3z
Alden's brother is 4 years younger than his second sister. It means that his brother's age is
z - 4
His brother is 2. It means that
z - 4 = 2
z = 2 + 4 = 6
y = 3z
y = 3 × 6 = 18
Substituting y = 18 into y = x + 5, it becomes
18 = x + 5
x = 18 - 5 = 13
Since we don't want to use the Pythagorean Theorem on all of these, first we look for some Pythagorean Triples. Its very helpful to know some of the common ones, so here's a list:
3, 4, 5
5, 12, 13
7, 24, 25
8, 15, 17
So we either look for these or a multiple of these numbers.
The last one is the only one that fits because 15, 20, 25 is a multiple of the triple 3, 4, 5 by multiplying all of them by 5.
Thus, 15, 20, 25 forms a right triangle.
