Mathhhhhhhhhhhhh

Question

X+3y=15 and 2x-3y=-6 in substitution

Answer 1

X+3y=15 and 2x-3y=-6 in substitution

We Have two equations

X = 15 -3Y from Eq 1

Plug in Eq 2

2( 15 -3Y ) - 3Y = -6

30 - 6 Y - 3Y = - 6

30 - 9Y = -6

-9y = - 36

Y = 4

Plug this value of Y in Eq 1

X + 3 * 4 = 15

X + 12 = 15

X = 3

Answer 2

First lets solve for x because it is the easiest.

x+3y = 15

becomes

x = 15 - 3y.

Now we plug in the value of x in the second equation and then solve for y. I'll show each step.

2(15-3y) -3y = -6

30-6y-3y = -6 - First we multiply by 2

30-9y =-6 - Now we combine like terms

-9y = -36 - We subtract both sides by 30 to get the y terms by themselves

y=4 - Now divide by -9 to solve for y.

We can plug the value of y into either equation. I chose the first one as it is simpler. Again showing every step.

x+3y = 15

x +3(4) = 15 - first plug in the value of y

x+12 = 15 - multiply the two numbers.

x = 3 - subtract 12 from both sides to solve for x.

So the answer is x = 3 and y = 4