Answer:
x = 26; l = 137; m = 137
Step-by-step explanation:
If the lines are parallel, that means the measurements are too. As such, equal the two expressions together
5x + 7 = 8x - 71
add 71 to both sides
5x + 7 + 71 = 8x - 71 + 71
-71 and +71 cancel each other out
5x + 78 = 8x
subtract 5x from both sides
5x - 5x + 78 = 8x - 5x
5x - 5x cancels each other out
78 = 3x
divide both sides by 3
3x ÷ 3 = 1x which can also be written as just x
78 ÷ 3 = x
26 = x
plug in this x value into both expressions to find variables l and m
l:
5(26) + 7
130 + 7
137
m:
8(26) - 71
208 - 71
137
