解:79+79×79等于( 6320 )
∵已知需求出79+79×79等于多少
X + X × Y = X × (1 + Y)
∴79 + 79 × 79
= 79 × (1 + 79)
= 79 × 80
= 6320
答:79+79×79等于6320
79+79×79
=79×(1+79)
=79×80
=6320
八,79看作80用80×80×80在-3×1。
79+79×79
=79×(1+79)
=(80-1)×80
=80×80-1×80
=6400-80
=6320
79X80=6320