Answer:
B.[tex]y-25=2(x-10)[/tex]
Step-by-step explanation:
The equation that will model the height [tex]y[/tex] of the plant after [tex]x[/tex] days will be of the form:
[tex]y=mx+b[/tex]
Where [tex]m[/tex] is the slope [tex]b[/tex] is the y-intercept.
The slope of the line is:
[tex]m=\frac{45cm-25cm}{20days-10days} =2\:(cm/day).[/tex]
Therefore we have
[tex]y=2x+b[/tex]
All we need now is the value of [tex]b[/tex].
We know that after 10 days the plant is 25 centimeters tall, or at [tex]x=10[/tex] [tex]y=25[/tex]; thus
[tex]25=2(10)+b[/tex]
[tex]\therefore b=5[/tex]
so we have the equation:
[tex]\boxed{y=2x+5}[/tex]
Of the four choices, choice B matches our result, because when we rearrange it and solve for y we get:
[tex]y-25=2(x-10)\\y=2(x-10)+25\\y=2x-20+25\\ \boxed{y=2x+5}[/tex]
