Question

Help !!!
See question in image.
Please show workings .
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Answer 1

`f(x) = 3 {x}^(2) \\ lim \: (f(x + h) - f(x))/(h) \: \: when \: h - > 0 \\ lim \: \frac{3( x + h)^(2) - 3 {x}^(2) }{h} when \: h - > 0 \\ lim \: \frac{3( {x}^(2) + 2xh + {h}^(2)) - 3 {x}^(2) }{h} when \: h - > 0 \\ \\ lim \: \frac{3 {x}^(2) + 6xh + 3h^(2) - 3 {x}^(2) }{h} when \: h - > 0 \\ lim \: \frac{6xh + 3 {h}^(2) }{h} \: when \: h - > 0 \\lim (6xh)/(h) + (3h^(2) )/(h)when \: h - > 0 \\ lim \: 6x + 3h \: when \: h - > 0 \\ = 6x + 3(0) \\ = 6x + 0 \\ = 6x \\ \\ or \\ (d(3x^(2)) )/(dx) = 2 * 3x^(2 - 1) \\ = 2 * 3x^(1) \\ = 2 * 3x \\ = 6x`