Ada yg tau cara kerjain nomor 4 gimana & caranya ya

√7-4√3 = √(2-√3)²
= 2 - √3

√(a+b)-2√(ab) = √a-√b
√7-4√3 = √7-(2×2)√3
= √7-(2×√4)√3
= √7-2√12 = √(4+3)-2√(4.3)
= √4-√3
= 2-√3