Question

how to isolate y from y-1=m(x-1)

Answer 1

y - 1 = m(x - 1)

first distribute the m to each monomial located in the parenthesis

m(x - 1) 
m(x) = mx
m(-1) = m(-1)

y - 1 = m(x) - m

isolate the y, add 1 to both sides

y - 1 (+1) = m(x) - m (+1)

y = m(x) - m + 1


y = m(x) - m + 1 should be your answer

hope this helps