Question

Дорешайте как в тетраде

Answer 1

$7 \times 65 + 7 \times 35 + 3 \times 35 + 3 \times 55 = \\ = 7 \times (65 + 35) + 3 \times (35 + 55) = \\ = 7 \times 100 + 3 \times 90 = 700 + 270 = 970$

Answer 2

= 7*100+3*90=700+270 = 970