Question

solve this math equation be fast . . . . . .. . . . .. . . . . . . solve 36th number pls do this​

Answer 1

Solution:-

1. Answer

We have,

=> x + y = 13 ....(i) eq

=> 2x + 3y = 10 .....(ii) eq

Now take

=> x + y = 13

=> x = 13 - y ....(iii)eq

Put the value of x on (ii)eq

=> 2x + 3y = 10

=> 2( 13 - y ) + 3y = 10

=> 26 - 2y + 3y = 10

=> 26 + y = 10

=> y = 10 - 26

=> y = - 16

Now put the value of y on (iii) eq

=> x = 13 - y

=> x = 13 - ( - 16 )

=> x = 13 + 16

=> x = 29

So value of x = 29 and y = - 16

2. Answer

Formula

=> Sₙ = n/2 { 2a + (n - 1 )d }

Now take

Given

=> S₇ = 49

=> n = 7

So

=> 49= 7/2 { 2a + ( 7 - 1 )d }

=> 49 × 2 = 7{ 2a + 6d }

=> 98/7 = 2a + 6d

=> 2a + 6d = 14 ....(i) eq

Now take

Given

=> S₁₇ = 289

=> n = 17

So

=> 289 = 17/2 { 2a + (17 - 1 )d}

=> 578 = 17 ( 2a + 16d )

=> 34 = 2a + 16d

=> 2a + 16d = 34 ......(ii) eq

Now subtract (ii)eq from (i)

=> 2a + 6d - 2a - 16d = 14 - 34

=> - 10d = - 20

=> d = 2

Now put the value of d on (i)eq

=> 2a + 6d = 14

=> 2a + 6 × 2 = 14

=> 2a + 12 = 14

=> 2a = 14 - 12

=> 2a = 2

=> a = 1

so a = 1 and d = 2

Answer 2

Answer:

x+y=13 (i)

x=13-y. (ii)

2x+3y=10 (iii)

Substitute value of x in equation (iii)

therefore,

2(13-y)+3y = 10

26-2y+3y = 10

26-10-2y+3y = 0

16+y = 0

y = -16

Subscribe y=-16 in eqn(ii)

x=13-(-16)

x=13+16

x=29

therefore x=29 and y=-16