a) \(35{x^2}-{\rm{ }}37x{\rm{ }} + {\rm{ }}2{\rm{ }} = {\rm{ }}0\) có \(a = 35, b = -37, c = 2\)
Do đó: \(a + b + c = 35 + (-37) + 2 = 0\)
nên \(\displaystyle {x_1} = 1;{x_2} = {2 \over {35}}\)
b) \(7{x^2} + {\rm{ }}500x{\rm{ }} - {\rm{ }}507{\rm{ }} = {\rm{ }}0\) có \(a=7, b = 500, c=-507\)
Do đó: \(a + b + c = 7 + 500 +(- 507)=0\)
nên \(\displaystyle{x_1} = 1;{x_2} = - {{507} \over 7}\)
c) \({x^2} - {\rm{ }}49x{\rm{ }} - {\rm{ }}50{\rm{ }} = {\rm{ }}0\) có \(a = 1, b = -49, c = -50\)
Do đó \(a - b + c = 1 - (-49) +(- 50) = 0\)
nên \(\displaystyle{x_1} = - 1;{x_2} = - {{ - 50} \over 1} = 50\)
d) \(4321{x^2} + {\rm{ }}21x{\rm{ }} - {\rm{ }}4300{\rm{ }} = {\rm{ }}0\) có \(a = 4321, b = 21, c = -4300\)
Do đó \(a - b + c = 4321 - 21 + (-4300) = 0\)
nên \(\displaystyle{x_1} = - 1;{x_2} = - {{ - 4300} \over {4321}} = {{4300} \over {4321}}\).
