X=4
26x - 4 = 100
+4 +4
26x = 104
x = 104/26
x=4
--------------------
If the area of a square is 169, what is the length of its side?
13 = sqrt169
--------------------
-4x + 8y = 2
-4x + 4x + 8y = 2 + 4x
8y = 4x + 2
8 8
y = ¹/₂x + ¹/₄
Eliminate x's by adding te 2 equations
add them
-2x+15y=24
<u>2x+9y=24 +</u>
0x+24y=48
24y=48
divide both sides by 24
y=2
sub back
2x+9y=24
2x+9(2)=24
2x+18=24
minus 18 both sides
2x=6
divide 2
x=3
x=3
y=2
(x,y)
(3,2)
bearing in mind that standard form for a linear equation means
• all coefficients must be integers, no fractions
• only the constant on the right-hand-side
• all variables on the left-hand-side, sorted
• "x" must not have a negative coefficient

![\bf \begin{array}{|c|ll} \cline{1-1} \textit{point-slope form}\\ \cline{1-1} \\ y-y_1=m(x-x_1) \\\\ \cline{1-1} \end{array}\implies y-7=1[x-(-1)]\implies y-7=x+1 \\\\\\ y=x+8\implies \boxed{-x+y=8}\implies \stackrel{\textit{standard form}}{x-y=-8}](https://tex.z-dn.net/?f=%5Cbf%20%5Cbegin%7Barray%7D%7B%7Cc%7Cll%7D%20%5Ccline%7B1-1%7D%20%5Ctextit%7Bpoint-slope%20form%7D%5C%5C%20%5Ccline%7B1-1%7D%20%5C%5C%20y-y_1%3Dm%28x-x_1%29%20%5C%5C%5C%5C%20%5Ccline%7B1-1%7D%20%5Cend%7Barray%7D%5Cimplies%20y-7%3D1%5Bx-%28-1%29%5D%5Cimplies%20y-7%3Dx%2B1%20%5C%5C%5C%5C%5C%5C%20y%3Dx%2B8%5Cimplies%20%5Cboxed%7B-x%2By%3D8%7D%5Cimplies%20%5Cstackrel%7B%5Ctextit%7Bstandard%20form%7D%7D%7Bx-y%3D-8%7D)
just to point something out, is none of the options, however -x + y = 8, is one, though improper.