I think B i am not 100 sure
3x-13=2
move -13 to the other side
sign changes from -13 to +13
3x-13+13=2+13
3x=2+13
3x=15
divide both sides by 3 to get x by itself
3x/3=15/3
cross out 3 and 3, divide by 3 and then becomes 1*1*x=x
x=15/3
x=5
answer:
x=5
Answer:
7. 36 8. 1 9. 21
Step-by-step explanation:
You plug in the variables in the equation.
7.
8. 
9. 
Differentiate both sides wrt 
:
By the chain rule, we get
Solve for 
:
We have an isosceles triangle;
A=opposite angle side a.
B=opposite angle side b.
C=opposite angle side c.
A=B
Method 1:
We can divide the isosceles triangle in two right triangles,
hypotenuse=7
side=9/2=4.5
B=A=arccossine (4.5/7)=49.994799...º≈50º
C/2=90º-50º=40º ⇒ C=2*40º=80º
Answer:
a=7; A=50º
b=7; B=50º
<span>c=9; C=80º
Method 2:
Law of cosines:
a²=b²+c²-2bcCosA ⇒CosA=(a²-b²-c²)/(-2bc)
CosA=(49-49-81) / (-126)=0.642857
A=arco cos (81/126)≈50º
B=A=50º
A+B+C=180º
50º+50º+C=180º
C=180º-100º
C=80º
Answer:
</span>a=7; A=50º
b=7; B=50º
<span>c=9; C=80º</span>
