Simplifying · Three Variables · D4

Big mixed brackets.

Several brackets at once: distribute each, then collect all three letters. 3(x + y) + 2(y + z) + x = 4x + 5y + 2z.

01 / THE IDEA

See it simplify.

Watch it simplify

Big mixed brackets

Expand both brackets, then collect x, y, z.

1 / 3
3(x+y)+2(y+z)+x3(x + y) + 2(y + z) + x
1

Distribute

Multiply out the brackets — every term inside by the factor in front.

3x+3y+2y+2z+x3x + 3y + 2y + 2z + x
2

Group like terms

Gather the terms that share the same variable part.

(3x+x)+(3y+2y)+2z(3x + x) + (3y + 2y) + 2z
3

Combine

Add the coefficients within each group.

4x+5y+2z4x + 5y + 2z
02 / YOUR TURN

Practice until it feels automatic.

Your turn

Simplify it.

Type the simplest form (e.g. 6x + 5). Use ^ for powers.

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— / WHY IT WORKS

The idea underneath.

Track many brackets

Distribute 3(x + y) and 2(y + z), then gather: xs 3 + 1 = 4, ys 3 + 2 = 5, zs 2. Result 4x + 5y + 2z.

Why it works

Open all the boxes, then sort.

03 / WORKED EXAMPLES

From easy to tricky.

EX 1easy

3(x + y) + 3(y + z) + 4x

1

Distribute

Multiply out the brackets — every term inside by the factor in front. → 3x + 3y + 3y + 3z + 4x

2

Group like terms

Gather the terms that share the same variable part. → (3x + 4x) + (3y + 3y) + 3z

3

Combine

Add the coefficients within each group. → 7x + 6y + 3z

EX 2medium

7(x + y) + 9(y + z) + 7x

1

Distribute

Multiply out the brackets — every term inside by the factor in front. → 7x + 7y + 9y + 9z + 7x

2

Group like terms

Gather the terms that share the same variable part. → (7x + 7x) + (7y + 9y) + 9z

3

Combine

Add the coefficients within each group. → 14x + 16y + 9z

EX 3hard

11(x + y) + 5(y + z) + 11x

1

Distribute

Multiply out the brackets — every term inside by the factor in front. → 11x + 11y + 5y + 5z + 11x

2

Group like terms

Gather the terms that share the same variable part. → (11x + 11x) + (11y + 5y) + 5z

3

Combine

Add the coefficients within each group. → 22x + 16y + 5z

04 / COMMON TRAPS

Where students slip.

Trap

Forgetting a bracket.

Fix

Distribute every bracket before collecting.

Trap

Mixing the ys from different brackets wrongly.

Fix

Add all y-terms together: 3y + 2y = 5y.

05 / QUIZ

Test yourself.

The Test

12 problems across three tiers. Auto-graded on submit. Hints and a full walkthrough on every question. Your work is saved on this device — sign in to keep it across devices.

0/12Answered
How to answerType just the value. Formatting won't trip you up — we ignore spaces, capital letters, commas, and subscript style, so t₁ = 5, d = 3 and t1=5,d=3 both count. For a list of numbers, separate them with commas (e.g. 3, 10, 17).
Core

Core (4)

C1

Simplify 3(x + y) + 3(y + z) + 4x

Need a hint?
  • Distribute each bracket first.
  • Then collect x, y, and z.
C2

Simplify 6(x + y) + 4(y + z) + 4x

Need a hint?
  • Distribute each bracket first.
  • Then collect x, y, and z.
C3

Simplify 2(x + y) + 2(y + z) + 3x

Need a hint?
  • Distribute each bracket first.
  • Then collect x, y, and z.
C4

Simplify 6(x + y) + 2(y + z) + 6x

Need a hint?
  • Distribute each bracket first.
  • Then collect x, y, and z.
Apply

Apply (4)

A1

Simplify 7(x + y) + 9(y + z) + 7x

Need a hint?
  • Distribute each bracket first.
  • Then collect x, y, and z.
A2

Simplify 4(x + y) + 9(y + z) + 4x

Need a hint?
  • Distribute each bracket first.
  • Then collect x, y, and z.
A3

Simplify 3(x + y) + 8(y + z) + 3x

Need a hint?
  • Distribute each bracket first.
  • Then collect x, y, and z.
A4

Simplify 8(x + y) + 4(y + z) + 9x

Need a hint?
  • Distribute each bracket first.
  • Then collect x, y, and z.
Extension

Extension (4)

E1

Simplify 11(x + y) + 5(y + z) + 11x

Need a hint?
  • Distribute each bracket first.
  • Then collect x, y, and z.
E2

Simplify 7(x + y) + 10(y + z) + 4x

Need a hint?
  • Distribute each bracket first.
  • Then collect x, y, and z.
E3

Simplify 5(x + y) + 9(y + z) + 7x

Need a hint?
  • Distribute each bracket first.
  • Then collect x, y, and z.
E4

Simplify 12(x + y) + 7(y + z) + 7x

Need a hint?
  • Distribute each bracket first.
  • Then collect x, y, and z.