Give possible expressions for the length and breadth of each of the following rectangles, in which their areas are given:
(i) Area : 25a 2 – 35a + 12
(ii) Area : 35y 2 + 13y –12
Area = Length × Breadth
The expression given for the area of the rectangle has to be factorised. One of its factors will be its length and the other will be its breadth.
(i) 25a 2 – 35a + 12 = 25a2 - 15a - 20a + 12
= 5a(5a - 3) - 4 (5a - 3)
= (5a - 3) (5a - 4)
Therefore, possible length = 5a - 3
And, possible length = 5a - 4
(ii) 35y 2 + 13y –12 = 35y2 + 28y - 15y - 12
= 7y(5y + 4) - 3 (5y + 4)
= (5y + 4)(7y - 3)
Therefore, possible length = 5y + 4
And, possible breadth = 7y - 3
Write the coefficients of x 2 in each of the following:
(i) 2 + x 2 + x
(ii) 2 – x 2 + x 3
(iii) \(\frac{π }{ 2}\) x2 + x
(iv) √2 x -1
Which of the following expressions are polynomials in one variable and which are not? State reasons for your answer.
(i) 4x 2 – 3x + 7
(ii) y 2 + √2
(iii) 3 √t + t√2
(iv) y +\(\frac{ 2 }{ y} \)
(v) x 10 + y 3 + t 50
What are the possible expressions for the dimensions of the cuboids whose volumes are given below?
(i) Volume : 3x 2 – 12x
(ii) Volume : 12ky2 + 8ky – 20k