Question

麻糬麵包

請問詳解的1×14是怎麼來的

z
3.
(5 × 1+2) (3 × 1-4) + (5 × 2 + 2) (3 × 2 − 4) + (5 × 3+2) (3 × 3-4) +
·
+ (5 × 10 + 2) (3 × 10 -4 ) = p ( 1² + 2² + 3² + ...+10²) + q ( 1 + 2 + 3 + + 10) + r
請問 p = }}
2
²9= -14
• r = 180 °
= (15×1²-14×1-8) + (15×7²-14X2-8)
+(15x3-1+x3-8) + ... + (15X/0² -14X10-8)
= 15 (1²+ 2² + 3² +
1₁ P = 15 9 = -14
+ 10² ) - 14 (1+2+3+... +10)-8X10
V = so