2x + 21 = 35
hope this helps
no solution, they are all the same line
To find the answer, use
, and then use the equation
To find it's half life.
Your answer is, get the variable by itself.
The goal in solving an equation is to get the variable by itself on one side of the equation and a number on the other side of the equation. To isolate the variable, we must reverse the operations acting on the variable. We do this by performing the inverse of each operation on both sides of the equation.
<h3><u>
What is an equation?</u></h3>
In mathematics, an equation is a formula that expresses the equality of two expressions, by connecting them with the equals sign =
<h3><u>
3 types of equations</u></h3>
Thus, <u>option a</u> is your answer.
Learn more about equations here
https://brainly.in/question/5052814
to find the slope for the first one, use the formula 
(It's the slope formula)
so... 
then plug in... 
this line has a slope of 0
As for the miles problem, to find mph, the miles have to be at 1.
so... 
therefore, he drove 60.5 mph