body{margin:0;} noscript{z-index: 10000; position: fixed; display: block; height: 100%; width: 100%; background: #fff;} noscript .fa{font-size: 40px; display:block; color: #daa520;} noscript div{margin-top: 6%; padding-left: 20px; padding-right: 20px; text-align: center;} ! You must have JavaScript enabled to use this site.

Dashboard

Big Ideas Math Integrated I, 2016 View details

2. Solving Systems of Linear Equations by Substitution

Continue to next subchapter

Exercise 18 Page 227

What does y equal?

Error: Wrong variable substituted.
Correct: y=- 9

Practice makes perfect

In step 1, y was isolated correctly. In step 2, the expression from step 1 was substituted into the second equation and x was solved for correctly. In step 3, y was substituted with the value of x. This is the mistake. To solve it correctly, we should substitute the x with 6 and calculate the value of y.

3x+y=9

Substitute

x= 6

3( 6)+y=9

Multiply

18+y=9

SubEqn

LHS-18=RHS-18

y=- 9

The value of y is - 9.