Substituting X Into an Equation

Which of the following correctly shows substituting the first equation into the second equation?

• x + 3x = -32

• y + y = -32

• y = 3(x + y = -32)

• 3y + y = -32

Tags

CCSS.MATH.CONTENT.HSA.REI.C.6

CCSS.MATH.CONTENT.HSA.CED.A.3

Which of the following correctly shows substituting the first equation into the second equation?

• 5x = -x + 4

• 5(y + 4) + 6y = 13

• 5x + 6(-x + 4) = 13

• 5x + (-x + 4) = 13

Tags

CCSS.MATH.CONTENT.HSA.REI.C.6

CCSS.MATH.CONTENT.HSA.CED.A.3

Which of answer shows the correct steps to solve for x?

Tags

CCSS.MATH.CONTENT.HSA.REI.C.6

CCSS.MATH.CONTENT.HSA.CED.A.3

Which of the following can always be used to check your solution to your equation?

• distributive property

• difference

• substitution

• mean

Now that we know x = 3

(from the previous question).

Solve the system.

**Write your answer as an ordered pair**

Answer explanation

We know x = 3, so plug it into one of the equation to solve for y.

y = 3x - 5

y =3(3)-5

y = 9 - 5

y = 4

So our answer is (3,4).

Tags

CCSS.MATH.CONTENT.HSA.REI.C.6

CCSS.MATH.CONTENT.HSA.CED.A.3

• when x=6, y=21

• When x=5, y=17

• When x=4, y=13

• When x=3, y=0

Why does substitution help us solve a system of equations?

• It changes one variable to an expression using the other variable, so we can solve an equation that only has one variable at a time.

• It creates a problem with fewer steps.

• It puts both equations in slope-intercept form for easy graphing.

Which option shows the CORRECT substitution for this system?

Which option shows the CORRECT substitution for this system?

Which option shows the CORRECT substitution for this system?