8x²-22x+5 tell fast
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Answer:Given quadratic equation is 8x² - 22x - 21= 0.
On comparing with standard form of quadratic equation i.e ax² + bx + c =0,
Here, a = 8 , b= -22 , c= -21
Now,ac= 8 × -21= -168
Here, c have negative sign so we have to find the factors of 168 whose difference is - 22. Such factors 28 and 6
8x² - 22x - 21= 0
8x² - 28x +6x -21=0
4x (2x - 7) + 3(2x -7)= 0
(4x+3) ( 2x-7) = 0
(4x+3) = 0 or ( 2x-7) = 0
4x = 0-3 or 2x= 0+7
x = -¾, x = 7/2
Hence, roots of equation 8x² - 22x - 21= 0 are -¾ and 7/2.
Step-by-step explanation:
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