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一次函数是一种常见的函数,也是最基本的函数,它与一元一次方程、一元一次不等式以及二元一次方程组有着密切的联系.下面列举几例,看看它们究竟有着怎样的联系.一、一次函数与一元一次方程例1自变量满足什么条件时,函数y=-2x+7的值为-2.解法1:令y=-2,得-2x+7=-2,解得x=4.5.解法2:由-2x+7=-2,得-2x+9=0.从图1可以看出直线y=-2x+9与x轴的交点坐标为(4.5,0),所以x=4.5.
A function is a common function, but also the most basic function, which has a close relationship with the linear equations, unary inequalities and binary systems. Here are a few examples to see if they have what kind of connection. , A function and a unitary equation Example 1 independent variables meet the conditions, the function y = -2x +7 value is -2. Solution 1: Let y = -2, -2x +7 = -2, the solution x = 4.5 Solution 2: -2x + 7 = -2, get -2x + 9 = 0. From Figure 1 we can see that the line y = -2x + 9 and the x-axis intersection coordinates (4.5,0), so x = 4.5.