According to my geometry notes two planes intersect at a line. Hope that helps:)
Answer:
b = 1
Step-by-step explanation:
-18+4b=7(4)+(7)-(6b)
-18+4b= 28 + (-42b)
4b-16=-42b+28
Add 42b to both sides.
4b-16+42b=-42b+28+42b
46b-18=28
Add 18 to both sides.
46b-18+18=28+18
46b=46
b= 46/46
b=1