1. จงเขียนนิพจน์ต่อไปนี้ให้อยู่ในรูปอย่างง่าย
1) 3x + 4x
วิธีทำ
3x + 4x
= (3 + 4) x
=7x
=7x
ตอบ 7x
2) 2a – a
วิธีทำ
2a – a
= (2 – 1) a
= a
= a
ตอบ a
3) 7a + 2a + 3a
วิธีทำ
7a + 2a + 3a
= (7 + 2 + 3) a
=12a
=12a
ตอบ 12a
4) 5x – 4x + 8x
วิธีทำ
5x – 4x + 8x
= (5 – 4 + 8) x
= 9x
= 9x
ตอบ 9x
5) 10m + 6m – m
วิธีทำ
10m + 6m – m
= (10 + 6 – 1) m
= 15m
= 15m
ตอบ 15m
6) 11a + 5a +7 – 4
วิธีทำ
11a + 5a +7 – 4
= (11a + 5a) + (7 – 4)
= (11 + 5) a + 3
= 16a + 3
= (11 + 5) a + 3
= 16a + 3
ตอบ 16a + 3
7) 16x – 4x – 10 + 3
วิธีทำ
16x – 4x – 10 + 3
= (16x – 4x) – (10 – 3)
= (16 – 4) x – 7
= 12x – 7
= (16 – 4) x – 7
= 12x – 7
ตอบ 12x – 7
8) \(\frac 1 2\)x + \(\frac 1 4\)x – x
วิธีทำ
\(\frac 1 2\)x + \(\frac 1 4\)x – x
= (\(\frac 1 2\) + \(\frac 1 4\) – 1) x
= (\(\frac{2+1-4}{4}\)) x
= – \(\frac{1}{4}\)x
= (\(\frac{2+1-4}{4}\)) x
= – \(\frac{1}{4}\)x
ตอบ – \(\frac{1}{4}\)x