3x-y=3, 9x-3y=9 solve the equations in substitution method

-

 2. Solve the following pair of linear equations by the substitution method.

(ii) 3x-y=3, 9x-3y=9

Solution:

  3x-y=3--------(1)

  9x-3y=9-------(2)

  Let we take equation (1) and make y form

  3x-y=3

  3x-3=y

  substitute y value in equation (2)

  9x-3y=9

  9x-3(3x-3)=9

  9x-9x+9=9

  9=9

Hence, the given equations have infinity many solutions 


Comments

Post a Comment

Popular posts from this blog

Half the perimeter of a rectangular garden, whose length is 4m-chapter 3 exercise 3.1 Q5

-
 5. Half the perimeter of a rectangular garden, whose length is 4 m more than its width, is 36 m. Find the dimensions of the garden. Rectangular Perimeter = 2(l+b) Half Perimeter = ½ x 2 (l+b) ½ x 2 (l+b) = 36  l+b = 36 --------(1) Length is 4 m more than its width l = b+4 --------(2) substitute l=b+4 in equation (1) l+b=36 b+4+b=36 2b=36-4 2b=32 b=16 b=8 substitute in equation (2) l=b+4 l=16+4=20 l=20, b=16
Read more

10 Students of Class X took part in a Mathematics quiz. if the number of girls is 4 more than the number of boys.

-
Image
Q(1). 10 students of class X take part in a Mathematics quiz. If the number of girls is 4 more than the number of boys, find the number of  boys and girls who took part in the quiz.  Solution: We do not know how many girls and how many boys Let be girls = X Let be boys = Y In question 10 number of students in class given  That means number of girls + boys = 10     X + Y = 10 ---------------(1) Number of girls is 4 more than the number of boys     X=Y+4 Now form the equation type Bring the Y this side of equal it will be –Y    X – Y = 4 ----------------(2) Now take equation (1) X + Y = 10 Move X that side of equal it will be –Y    Y = 10 – X We do not know what x values to take, do not confuse You can take x value from 1 and substitute in y equation form    Y=10-X    Y=10-1=9     Y=10-2=8    Y=10-3=7  Now make table       Now take equation (2)      X-Y=4 ...
Read more

A fraction becomes 9/11 , if 2 is added to both the numerator and the denominator. If, 3 is added to both the numerator and the denominator it becomes 5/6 . Find the fraction.

-
3. Form the pair of linear equations for the following problems and find their solution by substitution    method (v) A fraction becomes 9/11 , if 2 is added to both the numerator and the denominator. If, 3 is added to both the numerator and the denominator it becomes 5/6 . Find the fraction. Solution:    Let be numerator = x   Let be denominator = y     Fraction=x/y  If 2 is added in numerator and denominator to the fraction it becomes = 9/11      (x+2)/(y+2)=9/11      11(x+2)=9(y+2)      11x+22=9y+18      11x-9y+22-18=0      11x-9y+4=0---------(1)  If 3 is added in numerator and denominator to the fraction it becomes = 5/6     (x+3)/(y+3)=5/6     6(x+3)=5(y+3)     6x+18=5y+15     6x-5y+18-15=0     6x-5y+3=0---------(2)   By solving equation (1)     11x-9y+4=0     11x+4=9y     Y=(11x+...
Read more