Algebra 6

3 marks · Easy

Expand and simplify the following expression fully:

Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.

Show answer

x + 19

Must show: Expand 4(x + 2) to 4x + 8, Expand -3(x - 5) to -3x + 15, Combine like terms

Also accept: 19 + x

Common mistakes: Forgetting the negative sign for -3(x - 5)

Show mark scheme and worked solution

Marking points

M1 · 1 mark · Correctly expands 4(x + 2) to 4x + 8.

M2 · 1 mark · Correctly expands -3(x - 5) to -3x + 15.

A1 · 1 mark · Correctly combines terms to x + 19. (follow-through)

Worked solution

Expand each bracket:

Add together: 4x + 8 - 3x + 15 = (4x - 3x) + (8 + 15) = x + 23.

Wait, sum again - 8 + 15 is 23, not 19. Let's check working carefully: