Question

A)X elevado 2 -3x+15=0
B)X elevado 2 +3x-10=0
C)X elevado 2-4x-12=0
D)X elevado 2-X-40=0

Answer 1

bom dia !!!!!

$a) \\ \\ x {}^{2} - 3x + 15 = 0 \\ \\ x = \frac{ - ( - 3) + \sqrt{( - 3) {}^{2} } - 4 \times 1 \times 15}{2 \times 1} \\ \\ x = \frac{3 + \sqrt{9 - 60} }{2} \\ \\ x = \frac{3 + \sqrt{ - 51} }{2} \\ \\ = x \: \: e \: \: r \: \\ \\ \\ b) \\ \\ x {}^{2} + 3x - 10 = 0 \\ \\ x {}^{2} + 5x - 2x - 10 = 0 \\ \\ x \times (x + 5) - 2(x + 5) = 0 \\ \\ (x + 5) \times (x - 2) = 0 \\ \\ x + 5 = 0 \\ \\ x - 2 = 0 \\ \\ x1 = - 5 \\ x2 = 2 \\ \\ \\ c) \\ \\ x {}^{2} - 4x - 12 = 0 \\ \\ x {}^{2} + 2x - 6x - 12 = 0 \\ \\ x \times (x + 2) - 6(x + 2) = 0 \\ \\ (x + 2) \times (x - 6) = 0 \\ \\ x + 2 = 0 \\ \\ x - 6 = 0 \\ \\ x1 = - 2 \\ x2 = 6 \\ \\ \\ d) \\ \\ x {}^{2} - x - 40 = 0 \\ \\ x = \frac{ - ( - 1) + \sqrt{( -1) {}^{2} } - 4 \times 1 \times ( - 40) }{2 \times 1} \\ \\ x = \frac{1 + \sqrt{1 + 160} }{2} \\ \\ x = \frac{1 + \sqrt{161} }{2} \\ \\ x1 = \frac{1 - \sqrt{161} }{2} \\ \\ x2 = \frac{1 + \sqrt{161} }{2}$

espero que eu tenha conseguido te ajudar princesa...