Answer:
A
Step-by-step explanation:
the standard form of a quadratic equation is
ax² + bx + c = 0 : a ≠ 0
obtain (5 + x)(5 - x) = 7 in this form by expanding the factors
25 - x ² = 7 ( subtract 7 from both sides )
18 - x² = 0 ( multiply through by - 1 )
x² - 18 = 0 ← in standard form
with a = 1, b= 0 and c = - 18 → A
-212800
7.2 × 10³ = 7.2 × 1000 = 7200
2.2 × 10 to the power 5 = 2.2 × 100000 = 220000
7200 - 220000 = -212800
Check the picture below, notice the angles encircled in purple.
