An equation that goes through (-2, 1) and has a slope of 4 is y = 4x + 9.
You can find this by looking for the y-intercept (b) by using the slope (m), the point and slope intercept form. The work is below for you.
y = mx + b
1 = 4(-2) + b
1 = -8 + b
9 = b
Now we can use that and the slope to create the equation y = 4x + 9
To evaluate this expression you just have to substitue the value that is given.
so since we know m=2 x=7 y=5
and the expression is given mx-y
plug these values in as 2(7)-5 = 14-5 = 9
All the angles should add up to 360°.
8x+10x+9+21x-12+90=360°
Group like terms together.
So,8x+10x+21x+9+90-12=360
39x+87=360
39x=360-87
39x=273
x=7
