Mathematics: Solve the equation 4x+3y=18 3x+4y=3

Solve the equation 4x+3y=18 3x+4y=3 - id43183433899506, tynan74

Ответ:

savanah111

10.01.2022

Mathematics

(9,-6)

Step-by-step explanation:

4x+3y=18

3x+4y=3

Multiply the first equation by 3

3(4x+3y)=18*3

12x+9y = 54

Multiply the second equation by -4

-4(3x+4y)=3*-4

-12x -16y = -12

Add these two new equations together to eliminate x

12x+9y = 54

-12x -16y = -12

-7y = 42

Divide each side by -7

-7y/-7 = 42/-7

y = -6

Now we can find x

3x+4y =3

3x +4(-6) = 3

3x -24 =3

Add 24 to each side

3x-24+24 = 3+24

3x = 27

3x/3 = 27/3

x = 9

(9,-6)

0,0(0 оценок)

Ответ:

eggg65

10.01.2022

Mathematics

x = 9, y = -6

Step-by-step explanation:

$\left\{\begin{array}{ccc}4x+3y=18&(1)\\3x+4y=3&(2)\end{array}\right\\\\(1)\\4x+3y=18\qquad\text{subtract}\ 4x\ \text{from both sides}\\3y=-4x+18\qquad\text{divide both sides by 3}\\y=-\dfrac{4}{3}x+6\qquad\text{substitute it in (2):}\\\\3x+4\left(-\dfrac{4}{3}x+6\right)=3\qquad\text{use the distributive property}\\\\3x+(4)\left(-\dfrac{4}{3}x\right)+(4)(6)=3\\\\3x-\dfrac{16}{3}x+24=3\qquad\text{multiply both sides by 3}\\\\9x-16x+72=9\qquad\text{subtract 72 from both sides}\\\\-7x=-63\qquad\text{divide both sides by (-7)}\\\\\boxed{x=9}$