Write the exponential form:
Substitute each point in for (x, y) forming two equations and two unknowns.
y = (a)bx + 10
6 = (a)(b)4 + 10
8 = (a)(b)7 + 10
Solve for 'a' and 'b' and substitute the contants into the function.
Using the new function, substitute '0' for 'x' and simplify. This is the y-intercept.