Question

Please help me ASAP! multiple choice

Answer 1

Hi there!

Following are th' pair of linear Eqn :-

x + 7y = 15 ---(i)
8x + 4y = 16 ---(ii)

To eliminate " x " from th' Eqⁿ

Subtract eqn (i) × 8 from eqn (ii) :-

⇒ 8x + 4y - 8x - 56y = 16 - 120

⇒ - 52y = - 104

⇒ y = $\dfrac {- 104}{- 52}$

⇒ $\bf{y = 2}$

Substitute value of " y " in Eqn. (i) :-

x + 7y = 15

⇒ x + 7(2) = 15

⇒ x + 14 = 15

⇒ x = 15 - 14

⇒ $\bf {x = 1}$

Soln. of the Eqn. = (x, y) = (1, 2)

Hence,
Option 3ʳᵈ : (1, 2) is Correct.

~ Hope it helps!

Answer 2

So it goes as

8x+4y=16

7y=15-x

I want x by itself in the second equation so I subtracted 15 from both sides

7y-15=-x

I then divided each side by -1 to get

x=-7y+15

Now that I have x, I can plug that into the first equation to get:

8(-7y+15)+4y=16

Factor:

-56y+120+4y=16

Combine like terms and subtract both sides by 120

-52y=-104

Divide both sides by -52 to get y by itself

y=2

Therefore, the coordinates are (1,2) or C .