Replace Variables

What are the variables in the following expression?

• 3, 4, 1 and 7

• z, x and y

• + and -

• 15

Define substitute.

• the number multiplied by a variable

• to replace a variable with a value or an expression

• a number standing alone

• to find the value of an expression

substitution

• to replace one element of a mathematical equation or expression with another

• S and operation symbols

• an expression

Determine which method would be the best method given the system below.

-8x - 2y = -4

y = -8x - 2

• Substitution: Replace y in the top equation with -8x - 2

• Elimination: Cancel out y variables right away

• Substitution: Replace y in bottom equation with -8x - 2y

• Elimination: Cancel out x variables right away

Determine which method would be the best method given the system below.
8x - y = -8
y = 6x + 4

• Substitution: Replace y in the top equation with 6x + 4

• Elimination: Cancel out y variables right away

• Substitution: Replace x in bottom equation with 8x - y

• Elimination: Cancel out x variables right away

Determine which method would be the best method given the system below.

y = 2x - 6

-7x - 4y = -6

• Substitution: Replace y in the bottom equation with 2x - 6

• Elimination: Cancel out y variables right away

• Substitution: Replace x in bottom equation with 2x - 6

• Elimination: Cancel out x variables right away

Determine which method would be the best method given the system below.

x = 4y - 12

-14y - 8x = -12

• Substitution: Replace y in the bottom equation with 4y - 12

• Elimination: Cancel out y variables right away

• Substitution: Replace x in bottom equation with 4y - 12

• Elimination: Cancel out x variables right away

Determine which method would be the best method given the system below.
y = x + 9
y = 6x + 24

• Substitution: Replace y in the bottom equation with x + 9

• Elimination: Cancel out y variables right away

• Substitution: Replace x in bottom equation with x + 9

• Elimination: Cancel out x variables right away

replacing a variable with a number or expression

• equivalent fractions

• substitution

• evaluate

• equivalent expressions

• similar figures

a letter that represents an unknown value

• evaluate

• equivalent ratios

• variable

• substitution

• expression