Answer:
Explanation:
For the graphing, we can graph both equations, and where they intercept is the answer. Okay, so we can give x random inputs and get y as an output which is one pair of coordinates. I usually like using 0 as x. y-3(0)=12. y-0=12. y=12. So for our first equation, on of the coordinates is (0,12). Now we can insert another input for x! ( I chose 1.) y-3(1)=12. y-3=12. y=15. So our other pair of coordinates for the first equation is (1,15). We can do the same with the second equation. 2y+8(0)= -4. 2y+0= -4. y=-2. The first pair of coordinates for the second equation is (0,-2). Another input we can put in is 1, again. 2y+8(1)=-4. 2y+8=-4. 2y= -12. y= -6. So our second pair of coordinates for our second equation is (1,-6). We can graph this with a graphing calculator, or mark these points and draw a straight line through them. When we draw a line through them, the part where the two lines intersect is the answer.
When we do substitution, we need to solve for x or y in the bottom equation. I want to solve for x. ( NOTE: IF YOU SOLVE FOR y, YOU STILL GET THE SAME ANSWER) x=-56-3y. Then we replace the x on the top equation with 56-3y. And we get: 2(56-3y)-y=0. We can use the distributive property. The answer I have is 112-6y-y=0. -6y-y is -7y. 112-7y=0. We can add 7y to both sides so they seperate the variables and the numbers. 112=7y. Lastly, divide by 7. For y, we get 16. To get x, we insert y, AKA 16 into x+3y= -56. x+3(16)=-56. x+48= -56. Our last step to get x is to subtract 48 from both sides leaving us with: x= -100. Our final answer is y= 16 and x= -100.