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.

Pearson Algebra 1 Common Core, 2011

PA

Pearson Algebra 1 Common Core, 2011 View details

Cumulative Standards Review

Exercise 15 Page 414

You can solve for the variable by using the Cross Products Property.

x=6

Practice makes perfect

To solve the proportion, we will start by using the Cross Products Property. Remember that we will need to treat 21-x as a single quantity in the cross multiplication process.

2/5=x/21-x

Cross multiply

2(21-x)=5x

From here, we will continue solving for x by using the Distributive Property and the Properties of Equality.

2(21-x)=5x

Distribute 2

42-2x=5x

LHS+2x=RHS+2x

42=7x

.LHS /7.=.RHS /7.

6=x

Rearrange equation

x=6

Subchapter links

Exercises p.412-414