40乘以0.2x减0.25x=7怎么算?

40乘以0.2x减0.25x=7怎么算? (1乘以2x+3)+(x乘以-x)=0 怎么算 x乘以x+1乘以x+2乘以x+3=3024怎么解? 0.3x-x乘以0.25=21.15-7x 60乘以(x减1)等于40乘以(x加1)怎么做 X乘以X等于40 ---------------------X=? 2x^2+7x+5乘以x^2-2x-3怎么算 (1+40%)乘以X乘以80%—X=15 (1+40%)乘以X乘以80%—X=15 (1+40%)乘以X乘以80%—X=15 7乘以3-3x=6 怎么解 25x=25x乘以10乘以0.9+5x 怎么解 解方程2乘以0.2x-3乘以0.3x+5乘以0.4x=0.3乘以5 方程:15乘以(3x-8)-4乘以(2x+3)=6乘以(4x-4)-4怎么解 根号x 乘以sin x 的不定积分怎么算 dx/(x乘以根号下1+x^2)怎么算 55％x乘以2+10=x+20 怎么解 2x乘以x乘以x=24,求x! X-X乘以10%-X乘以20%=100 怎么才能算出X=多少?方法和最后答案 我主要想知道方法~