Advertisements
Advertisements
प्रश्न
`7x^2+3x-4=0`
उत्तर
`7x^2+3x-4=0`
⇒`49x^2+21x-28=0` (Multiplying both sides by 7)
⇒`49x^2+21x=28`
⇒`(7x)^2+xx7x xx3/2+(3/2)^2=28+(3/2)^2` [Adding (3/2)^2 on both sides]
⇒`(7x+3/2)^2=28+9/4=121/4=(11/2)^2`
⇒`7x+3/2=+-11/2` (Taking square root on both sides)
⇒`7x+3/2=11/2 or 7x+3/2=-11/2`
⇒`7x=11/2-3/2=8/2=4 or 7x=11/2-3/2=-14/2=-7`
⇒`x=4/7 or x=-1`
Hence, `4/7 and -1` are the roots of the given equation.
APPEARS IN
संबंधित प्रश्न
Solve the following quadratic equations by factorization:
`x^2-(sqrt2+1)x+sqrt2=0`
`8x^2-14x-15=0`
Solve the following quadratic equation by factorisation.
x2 – 15x + 54 = 0
Solve equation using factorisation method:
`x = (3x + 1)/(4x)`
Solve the following equation by factorization
`sqrt(3)x^2 + 10x + 7sqrt(3)` = 0
Solve the following equation by factorization
`(8)/(x + 3) - (3)/(2 - x)` = 2
Sum of two natural numbers is 8 and the difference of their reciprocal is 2/15. Find the numbers.
Rs. 7500 is divided equally among a certain number of children. Had there been 20 less children, each would have receive Rs 100 more. Find the original number of children.
A shopkeeper buys a certain number of books for Rs 960. If the cost per book was Rs 8 less, the number of books that could be bought for Rs 960 would be 4 more. Taking the original cost of each book to be Rs x, write an equation in x and solve it to find the original cost of each book.
Complete the following activity to solve the given quadratic equation by factorization method.
Activity: x2 + 8x – 20 = 0
x2 + ( __ ) – 2x – 20 = 0
x (x + 10) – ( __ ) (x + 10) = 0
(x + 10) ( ____ ) = 0
x = ___ or x = 2
