Sean is learning to scuba dive. The equation D = 20L + 15 represents the depth he can dive in feet, D, based on the number of lessons he has had, L. How deep can Sean dive after he takes 13 lessons?

Sean can dive 275 feet after he takes 13 lessons.

Step-by-step explanation:

Since L means the number of lessons taken, we will have:

D = 20*13 + 15

D = 260 +15

D = 275

step-by-step explanation:

5=812a+9+3

step 1: simplify both sides of the equation.

5=812a+9+3

5=(812a)+(9+3)(combine like terms)

5=812a+12

5=812a+12

step 2: flip the equation.

812a+12=5

step 3: subtract 12 from both sides.

812a+12−12=5−12

812a=−7

step 4: divide both sides by 812.

812a /812 = -7/812

a= -1/116

so the answer is

a=   -1/116