Question

if a+b=7 and ab=10; find a-b

Answer 1

HI FRIEND ✋✋

a + b = 7
a= 7 - b


ab = 10

(7-b)b = 10

7b - b² = 10

b² - 7b + 10 = 0

b² - 5b - 2b + 10 = 0

b( b - 5 ) - 2(b-5) = 0

b = 2 , b = 5
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when b = 2 , a = 5

therefore , a - b = 5 -2 = 3
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and when b = 5 , a = 2

a- b = 2-5 = -3


hope it helps

Answer 2

(a+b)²-(a-b)²=4ab
(a-b)²=(a+b)²-4ab
=7²-4*10
=49-40
(a-b)²=9
a-b=√9=3.