x means that it is used in algebra and that the value would be unknown and it is called variable
Step-by-step explanation:
for example: In x + 2 = 7, x is a variable, but we can work out its value if we try. A variable doesn't have to be "x", it could be "y", "w" or any letter, name or symbol.
The slope of line T is -1/5, because perpendicular lines have opposite reciprocal slopes, meaning the opposite sign (positive or negative) and flipped (whole number becomes a fraction).
