A linear system gives two equations that must hold for the same and . When parentheses make the algebra crowded, enter both equations as written in Desmos and click their intersection. The intersection satisfies both equations, so its coordinates give you and . Then evaluate the expression the question asks for, keeping any negative sign.
Hints
- Hint 1
Each equation makes a line, and an intersection is where the two lines cross. Enter each complete equation on its own Desmos line. You don't need to distribute the parentheses first.
- Hint 2
The minus sign before subtracts the whole expression. Keep those parentheses when you type the first equation, or you'll graph a different line.
- Hint 3
An ordered pair lists first and second. After clicking the crossing, write down both coordinates with their signs. What do you get when you add them?
Step-by-step
Graph the system in Desmos
Step 1Find the pair that satisfies both equations
Type and on separate Desmos lines. Keep the parentheses after the minus sign in the first equation. Click the intersection; Desmos shows . Because this point lies on both lines, its first coordinate gives and its second gives .
- Step 2
Add the coordinates
The question asks for , not either coordinate alone. Type ; Desmos shows . The second coordinate is negative, so you must keep its sign when adding. The value of is . Grid in -1.