PLEASE HELP ME

X^2+y^2=10
2x^2-2y^2=5
Solve with substitution

Aline has a slope of 1/4 and passes through point (0.4,-1/2). what is the value of the y-intercept?

If m∠abc = 70°, what is m∠abd? justify your reasoning.  using the addition property of equality, 40 + 70 = 110, so m∠abd = 110°.  using the subtraction property of equality, 70 − 30 = 40, so m∠abd = 30°.  using the angle addition postulate, 40 + m∠abd = 70. so, m∠abd = 30° using the subtraction property of equality.  using the angle addition postulate, 40 + 70 = m∠abd. so, m∠abd = 110° using the addition property of equality.

10x − 5y + 14 = 0 whats the answer pls