Question

вычислить$1) lim_{x to 4} frac{4x+5}{x-7} 2) lim_{x to 3} frac{ x^{2} -9}{x-3}$

Answer 1

$lim_{x to4} frac{4x+5}{x-7} = lim_{n to 4} frac{4*4+5}{4*1-7} = lim_{x to 4} frac{21}{-3} =- frac{21}{3} = -7$

$lim_{xto 3} frac{x^2-9}{x-3} = lim_{xto 3} frac{(x-3)(x+3)}{x-3} = lim_{xto 3} (x+3)=lim_{x to 3} (3+3) = 6$