Answer:
Equation 1: y = 2x + 7
Explanation:
In general the equation of a straight line is:
y=mx+c where m is the slope of the line and c is the y intercept
Or we can say that a graph is a straight line if it is a linear function.
Equation 1: y = 2x + 7
It is a linear function hence, its graph is a straight line
Equation 2: y² = x − 1
It is not a linear function hence, its graph is not a straight line
Equation 3: y = 2x² + 4
It is not a linear function hence, its graph is not a straight line
Equation 4: y = 3x³
It is not a linear function hence, its graph is not a straight line
Hence, The equation whose graph is a straight line is:
Equation 1: y = 2x + 7