Change the messy words into numerals
3 times a number minus 2 equals 13
3 × n - 2 = 13
3n - 2 = 13
take 2 to the other side
3n - 2 + (2) = 13 + (2)
3n = 15
Divide by 3 on either sides to isolate n

=

3 and 3 cancels out
n = 5
check:
3 times 5 minus 2 equals 13
3 × 5 - 2 = 13
15 - 2 = 13
13 = 13
The number is 5
Answer:
B = 62.9ft
Step-by-step explanation:
The distance where she is from the oak tree is 75ft,
The angle of elevation the stone makes with the top of the oak tree is 40°
The height of the tree is x ft
See attached document for better illustration
Using SOHCAHTOA,
Tanθ = opposite/ adjacent
θ = 40°
Opposite = x ft
Adjacent = 75ft
Tan40 = x / 75
X = 75 × tan40
X = 75 × 0.8390
X = 62.92ft
The height of the oak tree is 62.9ft
6 - 1/2z = 2/3
Steps
First, subtract 6 from both sides
6 - 1/2z - 6 = 2/3 - 6
Then, simplify
-1/2z = -16/3
Then, multiply both sides by -2
(-1/2z) (-2) = (-16/3) (-2)
Then, simplify
z = 32/3