(ii) 632 x 2 + (-98) (-632)
4. Find the product using suitable property:
(i) - 12 x (5 +9)
(iii) 173 (-35) + (-173) x 65
(v) 3455 x 192-455 x 192
(iv) 79 * (-99)+(-79)
(vi) - 95 x 2-(-95) - 98
Answers
Answer:
Because division removed a factor, it doesn't have t=0t=0 as a root. To be specific, the division is used to reject a solution while the product is used to add a solution.
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Example 1.
We need a different example to explain this. Let's take an example, the cube roots of unity. Say, we need the imaginary solutions only.
Let xx be the cube root of unity.
By its definition of cube root, the required equation is x^3=1x
3
=1 .
Given, x^3=1x
3
=1
\rightarrow x^3-1=0→x
3
−1=0
\rightarrow (x-1)(x^2+x+1)=0→(x−1)(x
2
+x+1)=0
We know the first factor results to x=1x=1 . To reject this, we divide by x-1x−1 to remove the factor.
\rightarrow x^2+x+1=0→x
2
+x+1=0
This leads to two imaginary solutions. So, we removed a real solution by division.
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Example 2.
Let's take a similar example but in the opposite way. Say, we need to know about the property of x^2+x+1=0x
2
+x+1=0 .
We multiply x-1x−1 to add a factor.
\rightarrow (x-1)(x^2+x+1)=0→(x−1)(x
2
+x+1)=0
\rightarrow x^3-1=0→x
3
−1=0
\rightarrow x^3=1→x
3
=1
So, we observe that the solutions of x^2+x+1=0x
2
+x+1=0 are the cube roots of unity. This happened because we added a solution from the multiplication.
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This is the required answer.
632 x 2 + (-98) (-632)
= 63200 Ans
4. i) - 12 x (5 +9)
= -168 Ans
iii) 173 (-35) + (-173) x 65
= -17300 Ans
v) 3455 x 192-455 x 192
= 576000 Ans
iv) 79 * (-99)+(-79)
= -7900 Ans
Hope it helps!!