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Standard XII

Mathematics

Definition of Functions

If a - b = ...

Question

If $a - b = 0.9$ and $a b = 0.36$ ; find $a + b$ .

\pm 2

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\pm 1.5

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Solution

The correct option is B $\pm 1.5$
$a - b = 0.9$ and $a b = 0.36$
Now,
$(a + b)^{2} = (a - b)^{2} + 4 a b$
$=> (a + b)^{2} = (0.9)^{2} + 4 (0.36)$
$=> (a + b)^{2} = 0.81 + 1.44$
$=> (a + b)^{2} = 2.25$
$=> (a + b) = \sqrt{2.25}$
$=> a + b = \pm 1.5$

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Similar questions

Q. If

a - b = 0.9

and

a b = 0.36

, then find

a^{2} - b^{2}

Q. If

a + b = 0.9

and

a b = 0.36

; find:
(i)

a - b

(ii)

a^{2} - b^{2}

Q. If

a - b = 0.9

and

a b = 0.36

, then find

a + b

Q. If

a - b = 0.9

and

a b = 0.36

; find

a^{2} - b^{2}

Simplify

(i) ${(\frac{3}{2} x - 0.45 y)}^{2}$

(ii) $(0.3 x - 0.2 y) (0.9 a - 0.02 b)$

(iii) $(0.3 a - 0.2 b) (0.09 a^{2} + 0.06 a b + 0.04 b^{2})$

(iv) ${(0.7)}^{3} + {(0.3)}^{3} + 3 \times 0.7 \times 0.3 (0.7 + 0.3)$

(v) ${(3.5)}^{3} - {(1.5)}^{3} - 3 \times 3.5 \times 1.5 (3.5 - 1.5)$

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If a−b=0.9 and ab=0.36; find a+b.

The correct option is B ±1.5 a−b=0.9 and ab=0.36Now,(a+b)2=(a−b)2+4ab=>(a+b)2=(0.9)2+4(0.36)=>(a+b)2=0.81+1.44=>(a+b)2=2.25=>(a+b)=√2.25=>a+b=±1.5

If $a - b = 0.9$ and $a b = 0.36$ ; find $a + b$ .

The correct option is B $\pm 1.5$
$a - b = 0.9$ and $a b = 0.36$
Now,
$(a + b)^{2} = (a - b)^{2} + 4 a b$
$=> (a + b)^{2} = (0.9)^{2} + 4 (0.36)$
$=> (a + b)^{2} = 0.81 + 1.44$
$=> (a + b)^{2} = 2.25$
$=> (a + b) = \sqrt{2.25}$
$=> a + b = \pm 1.5$