ok so im very new to calculus and just started learning limits...were exiting logs and entering limits (im a grade 12 student) my teacher has given me 2 question that have got me stumped.. here they are if anyone can help me out pllleaase help:) thanks:)

solve for x

2^x - 2^-x =4

2)determine the equation of both lines that are tangent to the graph of

f( x)=x^2

and pass through point

(1 , -3)

Must use

lim F( x ) - F ( a ) / x - a

x->a