Answer:
3
Step-by-step explanation:
Hello There!
First things first, we should find the rate of change / slope
given two points we can find the slope by using the slope formula which is
(let m be slope)
[tex]m = \frac{y_2-y_2}{x_2-x_2}[/tex]
To find the slope all we have to do is plug in the points
(1,5),(2,10)
remember the first numbers in an ordered pair are the x values and the second numbers are the y values
we also plug in the points of the second ordered pair first so
[tex]m=\frac{10-5}{2-1} \\10-5=5\\2-1=1\\m=\frac{5}{1} or5[/tex]
Knowing the slope we can create an equation to find the x value (a)
y=5x
given the y value we plug in y and solve for x
15=5x
divide each side by 5
15/5=3
5x/5=x
we're left with
x=3
so we can conclude when y =15 x = 3 therefore 3 is your answer
