Answer:
y = 3x + 7
Step-by-step explanation:
First, we will solve for the slope (m).
The formula for slope is: m = ![\frac{y2 - y1}{x2 - x1}](https://tex.z-dn.net/?f=%5Cfrac%7By2%20-%20y1%7D%7Bx2%20-%20x1%7D)
m =
--- enter the points into the formula
m =
--- simplify
m = 3 --- simplify
Now we will solve for the y-intercept (b).
y = mx + b
y = 3x + b --- substitute the slope into the equation
-20 = 3(-9) + b --- substitute the x and y of either point into the equation
-20 = -27 + b --- simplify
7 = b --- add 27 to both sides
b = 7
Done.
y = 3x + 7
divide 25 by 3 and 42 by three and plot those numbers
In case the user wants to see workings. These problems can easily be solved on a calculator, but can we work them out in our heads? ;)
9.34-3.029
=9.340-3.029
=9.340-3.000-0.029
=6.340-0.029
=6.311
![\bf \textit{logarithm of factors}\\\\ log_{{ a}}(xy)\implies log_{{ a}}(x)+log_{{ a}}(y) \\\\\\ \textit{Logarithm Change of Base Rule}\\\\ log_{{ a}}{{ b}}\implies \cfrac{log_{{ c}}{{ b}}}{log_{{ c}}{{ a}}}\\\\ -------------------------------\\\\ log_6(3)+log_6(72)=x\implies log_6(3\cdot 72)=x\implies log_6(216)=x \\\\\\ \cfrac{log(216)}{log(6)}=x\impliedby \textit{using the change of base rule}](https://tex.z-dn.net/?f=%5Cbf%20%5Ctextit%7Blogarithm%20of%20factors%7D%5C%5C%5C%5C%0Alog_%7B%7B%20%20a%7D%7D%28xy%29%5Cimplies%20log_%7B%7B%20%20a%7D%7D%28x%29%2Blog_%7B%7B%20%20a%7D%7D%28y%29%0A%5C%5C%5C%5C%5C%5C%0A%5Ctextit%7BLogarithm%20Change%20of%20Base%20Rule%7D%5C%5C%5C%5C%0Alog_%7B%7B%20%20a%7D%7D%7B%7B%20%20b%7D%7D%5Cimplies%20%5Ccfrac%7Blog_%7B%7B%20%20c%7D%7D%7B%7B%20%20b%7D%7D%7D%7Blog_%7B%7B%20%20c%7D%7D%7B%7B%20%20a%7D%7D%7D%5C%5C%5C%5C%0A-------------------------------%5C%5C%5C%5C%0Alog_6%283%29%2Blog_6%2872%29%3Dx%5Cimplies%20log_6%283%5Ccdot%2072%29%3Dx%5Cimplies%20log_6%28216%29%3Dx%0A%5C%5C%5C%5C%5C%5C%0A%5Ccfrac%7Blog%28216%29%7D%7Blog%286%29%7D%3Dx%5Cimpliedby%20%5Ctextit%7Busing%20the%20change%20of%20base%20rule%7D)
recall that, log <--- with no apparent base, implies base10, so you can just plug that in your calculator
for the change of base rule, it doesn't really matter what base you use, so long is the same above and below, it just so happen, that we used base10 in this case, but could have been anything, same result.