Find an equation for a square root function with domain [-0.5,infinity). please help!!

Consider a graph for the equation y= -3x+4. what is the y intercept? a) 4 b) -4 c) 3 d) -3

Scrub a dub toothbrushes are $4.00 each. there is a 10% discount, but there is also a 6% sales tax after the discount is applied. what is the new price after tax? round to the nearest penny

Determine which expressions represent real numbers and which expressions represent complex number. asaaap! plis!