Question

Solve the system of equations. \begin{aligned} & 7x-3y = 20 \\\\ & y=5x-4 \end{aligned} ​ 7x−3y=20 y=5x−4 ​

Answer 1

x=-1 & y=-9

Explanation:

7x-3y=20 ⇒(1)

y=5x-4 ⇒(2)

Multiplying (2) by 3

3y=15x-12 ⇒(3)

Add (1) and (3)

7x-3y+3y=20+15x-12

7x=15x+8

-8x=8

Substitute by x at (2)

y=5(-1)-4= -5-4=-9

x=-1 and y=-9