Respuesta :
1 Simplify brackets
7x-2y\times -4=17x−2y×−4=1
2 Simplify 2y\times -42y×−4 to -8y−8y
7x-(-8y)=17x−(−8y)=1
3 Simplify brackets
7x+8y=17x+8y=1
4 Subtract 8y8y from both sides
7x=1-8y7x=1−8y
5 Divide both sides by 77
x=\frac{1-8y}{7}x=
7
1−8y
7x-2y\times -4=17x−2y×−4=1
2 Simplify 2y\times -42y×−4 to -8y−8y
7x-(-8y)=17x−(−8y)=1
3 Simplify brackets
7x+8y=17x+8y=1
4 Subtract 8y8y from both sides
7x=1-8y7x=1−8y
5 Divide both sides by 77
x=\frac{1-8y}{7}x=
7
1−8y
They give you the value of y, y=-4, so you substitute this value for y into the other equation to get...
7x-2(-4)=1 perform indicated multiplication on left side...
7x+8=1 subtract 8 from both sides
7x=-7 divide both sides by 7
x=-1
So the solution to the system of equations is the point (-1,-4)
7x-2(-4)=1 perform indicated multiplication on left side...
7x+8=1 subtract 8 from both sides
7x=-7 divide both sides by 7
x=-1
So the solution to the system of equations is the point (-1,-4)