Answer:
a = 18
Step-by-step explanation:
2(a-7)=a+4
Distribute 2 into left side: 2a -14 = a + 4
subtract a from both sides 2a-a-14 = a+4-a
Simplify: a - 14 = 4
Add 14 to both sides: a - 14 + 14 = 4 +14
Simplify: a = 18
If wanted, plug a into original to double check work:
plug in: 2 (18-7) = 18+4
do parenthesis first: 2 (11) = 18+4
do multiplication : 22 = 18+4
additions: 22 =22
a = 18 is correct.
Answer:
A) 8, 15, 17.
Step-by-step explanation:
Right triangle obey the Pythagorean theorem. Thus, we choose the two smaller numbers (being the cathetus) and if after applying the P. Theorem we get the biggest of each option (the hypotenuse) that means that those numbers could be the sides of a right triangle.
The Pythagorean theorem states that: 
Thus:

Option A:
→ 17 = 17 OK!
Option B:
→ 10 ≠ 12 NO
Option C:
[/tex] →
≠ 21 NO
Option D:
→
≠ 16 NO
Answer:
Barium, Strontium and Beryllium
Explanation:
There are 18 groups in the periodic table and the previous 3 all belong to the same group, group 2 the alkali metals
Silicon is group 14, the carbon group
Aluminum is in the boron group, group 13
Osminium is in the group 8 transition metals
1) Formula: area = height * base / 2
2) Call x the height:
height = x
base = 2x
3) State the equation:
(x)(2x) = 49 in^2
4) Solve the equation:
2x^2 = 49 in^s
x^2 = (49/2) in^2
x = √(49/2) in
x = 7√2 / 2 in = 3.5 √2 in
5) Solution:
height = 3.5 √2 in and base = 7√2 in
6) Verification: area = (7√2 in) (3.5√2 in) = 49 in^2
Answer: height = 3.5√2 in and base = 7√2 in.
Answer:

Step-by-step explanation:
First, we can factor all of the following equations to turn that weird, huge looking thing into
÷
×
. We know that division is simply multiplication by the reciprocal, so that whole equation will turn into
×
×
. Now we can cancel out some values if they are both in the numerator and denominator, which will turn that still huge looking thing into
which is our final answer, as it cannot be simplified further.
Hope this helped! :)