Which are possible first steps in solving the equation 4^x+3=18?

[10 points, algebra 2]according to my answer key the restrictions are -1 and 4. but why not positive 1?

Which values of p and q result in an equation with exactly one solution? px-43=-42x+q choose all answers that apply: a) p=-43 and q=-43 b) p=42 and q=43 c) p=43 and q=−42 d) p=42 and q=42

Triangle knm is what is true about the sides of knm