Chapter 9.1, Problem 1CE

To determine

Calculate the value of y at the given value of x and sketch a graph.

Answer to Problem 1CE

The solution is,

  

Explanation of Solution

Given: The algebraic equations are given,

  $\begin{array}{l}2x-7y=9\\ x+y=0\end{array}$

Calculation:

Let’s take the first equation,

  $2x-7y=9$

Put the value of x, $x=0$

Then simplify the equation and calculate the value of y.

  $\begin{array}{l}2\times 0-7y=9\\ 7y=-9\\ y=-\frac{9}{7}\end{array}$

If we consider second equation $x+y=0$ then,

  $\begin{array}{l}0+y=0\\ y=0\end{array}$

program:

clc
clear
close all
symsxy
a=2*x-7*y-9;
b=x+y-0;
xx=1:5;
fori=1:5
    s=subs(a,x,i);
    sol(i)=solve(s);
    s1=subs(b,x,i);
    sol1(i)=solve(s1);
end
plot(xx,sol,'linewidth',1.2)
hold on
plot(xx,sol1,'linewidth',1.2)
set(gca,'linewidth',1.2,'fontsize',12)
xlabel('x')
ylabel('y')
axis square

Query:

• First, we have defined both the algebraic equations.
• Then define the value of x.
• Then put the value of x into both the equations and calculate the value of y.
• Sketch a graph for y at different value of x.