Substitute m = -2, c = 3 and x = -1 into y = mx + c to find y

Answer is y =  5

Step by step solution:

y = mx + c  

Where,

y= y coordinate

m = gradient (it is known as steepness of the slope)

x= x coordinate  

c = y intercept  

m = -2

c = 3  

x = -1  

y = ?

Substitute the values in the above equation  

y = mx + c  

y = -2 (-1) + 3

y = 2+3

y = 5

you can't solve x because it is 2 linear equation and you only have one equation