Step-by-step explanation:
You're asking why
let's transpose the first equation for y
-2x-6y=18
-6y=18+2x
6y=-18-2x
y=-18/6-2x/6
y=-3-⅓x as required
Answer:81030m
Step-by-step explanation:1km=1000m, 81km=81000+30=81030m
Answer:
A=100π=314.16 cm 2 to 5 significant figures
Step-by-step explanation: