Remember that
when solving a system of equations by graphing, the solution is the intersection of both graphs
so
Part A
we have
3(2^x)=6x-7
that is the same that
y=3(2^x)
y=6x-7
The solution is the x-coordinate of the intersection point in both graphs
using a graphing tool
There are no intersection points
that means
The system has no solution
Part B
we have
10x+5=-x+8
y=10x+5
y=-x+8
The solution is the x-coordinate of the intersection point in both graphs
using a graphing tool
The solution is x=0.27