153k views
3 votes
3x+5 = 4y - 15 ly+20= 1x + 15solve for x and y

User Frieder
by
4.2k points

1 Answer

0 votes

x=40

y=35

Step-by-step explanation


\begin{gathered} 3x+5=4y-15\text{ equation(1)} \\ y+20=x+15\text{ Equation(2)} \end{gathered}

Step1

isolate y from equation (2)y

now, replace y=x-5 in equation(1)


\begin{gathered} 3x+5=4y-15\text{ equation(1)} \\ 3x+5=4(x-5)-15\text{ } \\ 3x+5=4x-20-15 \\ \text{subtract 3x in both sides} \\ 3x+5-3x=4x-20-15-3x \\ 5=x-35 \\ \text{add 35 in both sides} \\ 5+35=x-35+35 \\ x=40 \end{gathered}

Step 2

replace the value of x= 40 in equation (3) to find y


\begin{gathered} y=x-5\text{ Equation(3)} \\ y=40-5\text{ } \\ y=35 \end{gathered}

I hope this helps you

User Edd Morgan
by
4.2k points