0.7x=4.2x=4.2÷0.7=6(10-7.5)x=11x=11÷2.5=4.4如果有帮助,请采纳并点赞,谢谢!
0.7X=4.2(10-7.5)X0.7X=42-31.5X0.7X+31.5X=4232.2X=42X=42/32.2X≈1.3。