tolong donk bantu aku ..tentang pelajaran mtk pake cara nya ..coba yg bisa mtk bantuin donk

4)
a.
6
Σ (n + 1)
i=1

b.
5
Σ (2n+3)
i=1

5)
a. (1+2)² + (2+2)² + (3+2)² + (4+2)² + (5+2)²
= 3²+4²+5²+6²+7² = 9+16+25+36+49
= 135

b. (3×1²+1) + (3×2²+2) + (3×3²+3)
= (3+1)+(12+2)+(27+3)
= 3+14+30 = 47

c. (2.1+3)+(2.2+3)+(2.3+3)+(2.4+3)+(2.5+3)+(2.6+3)+(2.7+3)
= 5+7+9+11+13+15+17
= 77

d. (3+1)+(4+1)+(5+1)+(6+1)+(7+1)+(8+1)
= 4+5+6+7+8+9
= 39