Answer: r = 4
Step-by-step explanation:
To solve the equation 15 r - 6 r = 13, every thing is in order, all we need to do is subtract and then make r subject of the formula
15 r - 6 r = 36
9 r = 36
we then divide both-side of the equation by 9 to make r subject of the formula. Hence;
[tex]\frac{9r}{9} = \frac{36}{9}[/tex]
(On the left hand side of the equation; 9 will cancel out 9 leaving us with r. On the right hand side of the equation 9 will divide 36 which will give us 4)
r = 4
Therefore, the value of r is 4
