Answers

2016-02-29T18:44:49+05:30
First let x = 3/4 for now
ax² + bx - 6 = 0
ax² + bx = 6
x(ax + b) = 6
ax + b = 6/x
3a/4 + b = 6 / (3/4)
3a/4 + b = (6 * 4) / 3
3a/4 + b = 24/3
3a/4 + b - 8 = 0 ---------------1
b = 8 - 3a/4 

Now 
Let x = -2
a(-2)² + b * -2 - 6 = 0
4a - 2b -6 = 0
4a - 2b  = 6 --------------2
So,
4a = 6 + 2b
  a = (6 + 2b)/4
Substituting the value of a in equation 1

3a/4 + b - 8=0
3(6 + 2b) / 16  + b = 8   taking LCM
(18 + 6b + 16b)/16 = 8
18 + 22b = 8 * 16
22b = 128 - 18
22b = 110
b = 110/22 = 5

Substituting The Value Of b in Equation 2
4a - 2b = 6
4a - 2*5 = 6
4a - 10 = 6
4a = 6 + 10
4a = 16
a = 16/4 = 4

Therefore the values of a and b are 4 and 5 respectively




 
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