-31-х=-9
-х=-9+31
-х=22
х=-22
<span>a-7 и a+8 при a=23 a=57 a=60 a=92</span>
<span>1. а=23</span>
<span>23-7=16, 23+8=31</span>
<span>2. а=57</span>
<span>57-7=50, 57+8=65</span>
<span>3. а=60</span>
<span>60-7=53, 60+8=68</span>
<span>4. а=92</span>
<span>92-7=85,92+8=100</span>
658:7*15=1410 уменьшаемое
1410-658=752 разность
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