1-a+2a-3- 1=0，a-3=0，a=3

2. The original formula is, y =-x 2+2x+3.

When x= 1, y =-12+2 *1+3 = 4.

14, substitute x value, 4(2-m)=2+2m.

8-4m = 2+2m

6m=6

m= 1