no
the table does not represent a proportional relationship.
For this case we must simplify the following expression:

We have that by definition of properties of powers that is fulfilled:

Then, rewriting the expression:

Answer:

The answer is 15.
17^2-8^2=225
sr of 225= 15
:))
So base on your question the possible answer to that kind of question and the solution are the following and i hope you will understand the formula and free to ask some questions if needed.
<span>2<span>cos2</span><span>x2</span>=1+cosx=1−<span>1517</span>=<span>217</span>,<span>cos2</span><span>x2</span>=<span>117</span></span>
<span>cos<span>x2</span>=−<span>1<span>17<span>−−</span>√</span></span>....(1)</span>
<span>sin<span>x2</span>=<span>1<span>17<span>−−</span>√</span></span>,90<<span>x2</span><135</span>
<span>sin<span>x2</span>>0,cos<span>x2</span><0,tan<span>x2</span><0</span>
<span>2<span>sin2</span><span>x2</span>=1−cosx=1−<span><span>−15</span>17</span>=<span>3217</span>,sin<span>x2</span>=<span>4<span>17<span>−−</span>√</span></span>.....(2)</span><span>
divide (2) by (1) and get the value of tan x/2</span>
Cost of company A=monthlyfee+text=20+0.03t where t=number of texts
A=20+0.03t
company b is monthlyfee+texts=5+0.07t
B=5+0.07t
1.
c=20+0.03t
c=5+0.07t
using c for cost is confusing because we can't tell which is for which company
2.
equal, means the costs are equal so
20+0.03t=5+0.07t
minus 5 from both sides
15+0.03t=0.07t
minus 0.03t from both sides
15=0.04t
divide both sides by 0.04
375=t
the answer is 375 texts