Question

Solve x and y
(i) 3x + 7y = 36
6x + 5y = 27
(ii) 11x + 2y =125
2x + lly = 44​

Answer 1

Answer:

3x + 7y = 36 6x + 5y = 27 (ii) 11x + 2y =125 2x + 1ly = 44. 1. See answer. Add answer+5 pts.

Answer 2

Answer:-

i.) y = 5 and x = 0.3

ii.) y = 2 and x = 11

Solution:-

i.) 3x + 7y = 36, 6x + 5y = 27

Case - I :-

3x + 7y = 36

3x = 36 - 7y

$\tt{x = \dfrac{36 - 7y}{3} \: \: \: ....eq.i.)}$

Case - II :-

6x + 5y = 27

6x = 27 - 5y

Substituting the value of x from eq. i.)

$= > \tt{6( \dfrac{36 - 7y}{3} ) = 27 - 5y} \\ \\ = > \tt{ \dfrac{216 - 42y}{3} = 27 - 5y} \\ \\ = > \tt{216 - 42y = 3(27 - 5y) }\\ \\ = > \tt {216 - 42y = 81 - 15y} \\ \\ = > \tt{- 42y + 15y = 81 - 216} \\ \\ = >\tt{ - 27 y= - 135} \\ \\ = >\tt{ y = \dfrac{ - 135}{ - 27} } \\ \\ = > \tt{y = 5}$

Value of y is 5.

Substituting the value of y in eq.i.)

$= > \tt{x = \dfrac{36 - 7y}{3} } \\ \\ = > \tt{x = \dfrac{36 - 7 \times 5}{3} } \\ \\ = > \tt{x = \dfrac{36 - 35}{3} } \\ \\ = > \tt{x = \dfrac{1}{3} } \\ \\ = > \tt{x = 0.3}$

ii.) 11x + 2y = 125, 2x + 11y = 44

Case - I :-

11x + 2y = 125

11x = 125 - 2y

$\tt{x = \dfrac{125 - 2y}{11} \: \: \: ....eq.i.)}$

Case - II :-

2x + 11y = 44

Substituting the value of x from eq.i.)

$= > \tt{2 (\dfrac{125 - 2y}{11})+11y = 44} \\ \\ = > \tt{\dfrac{250 - 4y}{11}+11y = 44} \\ \\ = > \tt{\dfrac{250 - 4y + (11y \times 11)}{11}= 44} \\ \\ = > \tt{\dfrac{250 - 4y + 121y}{11}= 44} \\ \\ = > \tt{\dfrac{250 + 117y}{11}= 44} \\ \\ = > \tt{250 + 117y= 44 \times 11} \\ \\ = > \tt{250 + 117y= 484} \\ \\ = > \tt{117y= 484 - 250} \\ \\ = > \tt{117y= 234} \\ \\ = > \tt{y= \dfrac{234}{117}} \\ \\ = > \tt{y = 2}$

The value of y is 2.

Substituting the value of y in eq.i.)

$= > \tt{x = \dfrac{125 - 2y}{11}} \\ \\ = > \tt{x = \dfrac{125 - 2 \times 2}{11}} \\ \\ = > \tt{x = \dfrac{125 - 4}{11}}\\ \\ = > \tt{x = \dfrac{121}{11}}\\ \\ = > \tt{x = 11}$